Foxglove (Digitalis purpurea L.). The Foxglove has been recognized as poisonous for centuries, and one of its trivial names is Dead Men’s Bells—a name suggestive of the consequences of taking it. It is the source of the well-known drug; and cases of human poisoning have been very common, though by no means always fatal—indeed, Esser says “seldom resulting in death.” Animals are not known to touch this plant, but it may possibly be included in rough meadow hay, though only one case, in which two cows and a horse became ill after eating hay containing dry foxgloves, has come to notice (Veterinary Record, 1906). Cornevin, however, experimented on animals, and found the following amounts of fresh leaves capable of causing death in the animals specified:—

The weight of dried leaves would be only one-fourth of these figures.

All parts of the foxglove are poisonous, but especially the seeds, and the leaves are more active before than after the flowering period. Cultivated varieties are stated to be less toxic than the wild species. The effects of poisoning may terminate fatally in a few hours, or if small quantities are taken regularly the poison may be cumulative and induce chronic poisoning.

Toxic Principle. The foxglove contains several poisonous glucosides, investigated by Kiliani, Schmiedeberg, Cloette, Bourquelot, Herzig, and others. The following substances are toxic: Digitalin (C₃₅H₅₆O₁₄ or C₃₆H₅₈O₁₄) in the seeds and leaves; Digitonin (C₅₄H₉₂O₂₈ or C₅₅H₉₄O₂₈) in the seeds; Digitalein, only in small quantity; Digitoxin (C₃₄H₅₄O₁₁) in the leaves; and Digitin. The toxic property of the foxglove is not lost on drying or boiling.

Symptoms. Digitalis is an active heart poison, and causes nausea, pressure in the region of the stomach, with diminished pulse, darkening of the field of vision, dizziness, buzzing in the ears, and usually dilated pupils.

According to Pammel the symptoms in animals are dullness, lassitude, loss of appetite, nausea, flatulence, diarrhoea; infrequent, full pulse (reduced 6–10 beats in the horse); and contracted pupils. In fatal cases these symptoms are followed by severe colic and tympanites; rapid, feeble, dicrotic, irregular or intermittent pulse (120–140 in horses), while the heart may be heard and felt beating wildly and strongly, and a systolic blowing murmur can frequently be detected. This is due to mitral or tricuspid regurgitation caused by irregular contraction of the columnÆ carnÆ. The pulse is imperceptible because of the failure of the heart to fill the vessels. The extremities are cold, the eye is protruding, and salivation occurs. Bloody diarrhoea is very often present and the urine may be suppressed. The breathing finally becomes difficult and death ensues within a few hours, or as late as several days.

The following account of the symptoms of poisoning in various animals is collected by Lander:—

Horses. On the first day sleepiness, swollen eyelids, dilated pupils, injected conjunctivÆ, considerable swelling in submaxillary space; respiration normal, temperature 103·5° F.; pulse full, between 65 and 75, very intermittent, being occasionally normal; the second heart sound frequently obliterated. On the next day laboured breathing, head immensely swollen, tongue greatly enlarged and protruding, pulse 80 and most erratic, temperature very slightly up, great restlessness. Respiration became more difficult and stertorous, tongue and buccal membranes livid, jugular standing out.

A mare experimentally poisoned showed on the third day dullness and loss of appetite; fourth day nauseated; nose, mouth, and ears cold; abdomen blown, with colicky pain, and occasional pawing; pupil somewhat contracted, pulse firm at axilla and heart, but not perceptible at jaw; at 4.30 p.m. she was down, much pained, and attempting to roll; pulse 82, but unequal; fifth day, pulse, imperceptible at jaw, about 120; respiration 25, and very much laboured: lips retracted and saliva dripping from the mouth; enormous abdominal tympanites, and much pain; rapid sinking: died sixth day.

Cows. Fed erratically, breathed hard, lay down after feeding. Pulse almost imperceptible, contracted pupil, and excessive urination.

Pigs. Languid and sleepy: refused to eat or drink, attempting to vomit and repeatedly passing small quantities of fÆces. Urination was scanty and strained.

In a case of poisoning among horses to which MÜller refers the animals had an exhausted appearance, there was loss of appetite, increasing thirst, often also colic, and later diarrhoea, urination often in great quantity, and staggering. Some of the animals died after a few days in convulsions.

Lousewort (Pedicularis, sp.). Two species of lousewort are involved, P. palustris L. and P. sylvatica L., and though both are regarded as poisonous the extent to which they are so is not well known. They have an unpleasant smell and sharp taste, and are in general refused by all classes of stock. P. sylvatica may be eaten when young (Cornevin). Lindley says that both plants are acrid, but are eaten by goats. P. palustris is regarded by Pott as an acutely poisonous plant, especially for sheep. A decoction of these plants was formerly used against lice, and hence the trivial name.

Toxic Principle. Very little appears to be known about the poisonous principle, but, like Rhinanthus and Melampyrum, they have been found to contain the glucoside Rhinanthin (see p. 96).

Symptoms. The plants are held to be emetic and purgative; to cause inflammation of the digestive tract, and to cause anÆmia in cattle. Brugmann stated (vide Cornevin) that if, pressed by hunger, animals eat P. palustris, the first consequence is hÆmaturia. MÜller also notes hÆmaturia.

POLYGONACEÆ.

Docks (Rumex sp.). In general it is probable that but little harm is done by species of Rumex, but owing to the fact that Common Sorrel (R. Acetosa L.) and Sheep’s Sorrel (R. Acetosella L.) contain acid oxalates they may on occasion prove injurious. Instances have been recorded in which children have suffered from eating the leaves of the former species in considerable quantity, and both species have been accused by veterinary surgeons of poisoning horses and sheep, some sheep even dying. Pammel states that the Curled Dock (R. crispus L.) induces nausea, watery brown fÆces, copious urination, dry spasmodic cough, and perspiration; but no record of the death of animals has been found.

In regard to R. Acetosella it is stated that in the horse a condition may be produced resembling drunkenness, with vacillating gait, salivation, muscular tremors, dilatation of pupils, relaxation of sphincters, and a feeble, slow, and intermittent pulse: then convulsive contraction of lips, retraction of the eyeball, accelerated and stertorous breathing, extreme dilatation of the nostrils, tetanic contraction of the muscles of the neck, back, and limbs, abundant sweating and falling. In bad cases after a period of extreme exhaustion, these symptoms are repeated, and death occurs in convulsions (Cornevin).

The acid oxalates seem especially harmful to sheep, causing loss of appetite, exhaustion, small and scarcely perceptible pulse, rapid breathing, and constipation, and in many cases severe diarrhoea, uncertain gait, and sometimes death (MÜller).

The milk of affected cows is with difficulty made into butter (Pott).

Polygonum sp. Several species of Polygonum are said to have poisonous properties. The chief among them is Buckwheat (P. Fagopyrum), the grain of which is widely grown as a food for both man and live stock. This plant, particularly the flowers, has given rise to a well-known rash in man, cattle, sheep, and pigs, with congestion and tumefaction—especially of the head and ears. There is also nervous disturbance, with agitation and hallucination—sheep, for example, may butt against objects. The affection of the nervous centres may lead to fatal results, which have followed in cattle, sheep, and pigs. Little is known of this so-called Fagopyrism, but after analytical and spectroscopical researches on the colouring matter of the tegument Kurt concluded that it is due to the chlorophyll.

Persicaria (P. Persicaria L.) and Water-pepper (P. hydropiper L.) are also stated to be harmful, though the former has been considered a nutritious plant and has been given to horses and cattle as a green food.

Both species, however, are said to cause a rash, and to contain injurious narcotic substances. Persicaria is stated by MÜller to have caused inflammation of the bladder and the digestive tract in pigs, and Water-pepper to have caused hÆmaturia; fatal results have followed. Pott records similar symptoms. In regard to Persicaria it should be noted that it varies considerably in general form, and may possibly vary also in acridity. Bentham and Hooker state of P. hydropiper that “the whole plant is more or less acrid or biting to the taste.”

THYMELACEÆ.

Mezereon (Daphne Mezereum L.) and Spurge Laurel (D. Laureola L.). Both of these species are acrid and poisonous, and cases of the death of horses due to the spurge laurel are recorded by Lander. In general, however, animals will not eat the plants, and indeed, in one of the cases mentioned by Lander the dried leaves were administered for worms. Should they touch these plants most animals would probably refuse them on account of their bitter taste. The berries are tempting to children, and Pratt says “Death has resulted from eating but a few of these berries (D. Mezereum); and Dr. Christison relates a case of a child, in Edinburgh, who died from eating them, while another is recorded by LinnÆus of a young lady to whom twelve of the berries were given as a medicine in intermittent fever, and who soon died in consequence of their corrosive poison. Four berries produced thirst, sense of heat in the mouth and throat, and also fever, in a man who ate them; and they are proved to be poisonous to dogs and foxes.” Blyth states that 30 grammes (1 oz.) of the powdered bark is a lethal dose for a horse, but smaller doses of the fresh leaves may be deadly (Pammel).

Toxic Principle. All parts of these plants are acrid and poisonous, especially the bark and berries. They contain the bitter, astringent, and poisonous glucoside Daphnin (C₃₀H₃₄O₁₉—or C₁₅H₁₆0_9 according to Van Rijn), an acrid resin (Mezerein), and a vesicating fatty oil. (Pott remarks that Daphnin is believed to be harmless, but that Mezerein has poisonous effects.) Drying does not destroy the poisonous property.

Symptoms. The Daphnes are severely purgative, cause burning in the mouth and throat, and in severe cases have narcotic effects and give rise to convulsions.

Lander gives the symptoms as intense colic, constipation, followed by dysentery and copious evacuations of fÆces streaked with mucus, blood, and intestinal epithelium. Drowsiness between the spasms.

According to MÜller there is inflammation of the stomach and intestines (with colic, vomiting, severe diarrhoea, passing of blood), inflammation of the kidneys (with strangury, bloody urination), and in many cases nervous symptoms (weakness, giddiness, and convulsions).

In a case observed by Lander, in the horse, there was abdominal pain, staggering gait, anxious countenance, laboured breathing, pulse 80, temperature 103·2° F., bowels normal. On the following day there was excessive purgation, pulse 120, temperature 104·2° F., and death occurred at mid-day.

EUPHORBIACEÆ.

Spurges (Euphorbia sp.). Many species of Spurge must be regarded as acrid, purgative, and poisonous. Live stock are not likely to touch them, owing to the acrid effect of the milky juice on the mouth.

The Caper Spurge (E. Lathyris L.) contains an acrid, emetic, and highly purgative milky juice, and the fruits have commonly been employed by country folk as a purge, and also as a pickle, though they are dangerous and should not be so used. Pratt records a case in which five women ate the pickled fruits with boiled mutton, and all suffered severe pain and burning in the stomach, and showed other symptoms attendant on irritant poisoning—and though all recovered the illness was severe. Used in this manner, indeed, they have given rise to serious cases of human poisoning. Only very young animals are said to eat it, but cattle in the United States are said to be “quite resistant to its influence, but they are sometimes overcome.” According to Chesnut goats eat this plant extensively, and it is said that their milk then possesses all the venomous properties.

Petty Spurge (E. Peplus L.) is somewhat similar to the Caper Spurge in poisonous properties, and fatal poisoning has occurred through a boy eating it.

Sun Spurge (E. Helioscopia L.) is similarly poisonous to the preceding species. It has caused fatal poisoning to a boy who ate it. In Germany cows were poisoned through pasturing in stubble in which the plant was growing, but there were no deaths.

Toxic Principles. The milky juice of these spurges contains highly acrid poisonous substances, which have not been individually and fully investigated. Drying may reduce the toxicity but does not eliminate it.

Symptoms. As regards E. Lathyris Chesnut says that on the skin the juice causes redness, itching, pimples, and sometimes gangrene. The seeds when eaten inflame the mouth and stomach, cause vomiting and intense diarrhoea, and if the illness is serious, nervous disorders, unconsciousness, collapse, and death.

The Euphorbias have an acrid effect on the mouth, and severe poisoning may follow their use as aperients—burning mouth, swelling tongue, stomach pains, cold skin, vertigo, fainting or syncope, and even death in two or three days (Esser).

Similar symptoms are given by Cornevin, who states that the Euphorbias have an irritating effect on the mucous membrane, especially at the back of the mouth. In from three quarters of an hour to two hours after eating the plant, or even longer, there is painful vomiting, followed by diarrhoeic evacuations, with a lowering of the temperature. If the quantity ingested has been sufficient there appear also nervous symptoms, vertigo, delirium, muscular tremors, and respiratory and circulatory troubles which disappear after abundant sweating if the poisoning is not fatal. If it is fatal the symptoms of superpurgation and enteritis predominate, but are accompanied by nervous symptoms and circulatory disorders.

MÜller gives in addition loss of appetite, piteous whining (in goats), groaning, colic and tympanites; and Pott, bloating, fever, palpitation of the heart, and loss of consciousness. Cows gave a reddish or sharp-tasting milk. Milk of affected goats caused diarrhoea human beings.

Dog’s Mercury (Mercurialis perennis L.) and Annual Mercury (M. annua L.). These two species may be taken together as they have similar poisonous properties, and closely resemble one another, though the former is a perennial and the latter an annual. The plants have a somewhat unpleasant odour, and live stock are not likely to take them unless pressed for readily available green food. The loss of one cow and severe illness of four others was recorded by Blackhurst in the Veterinary Journal in 1896; GÜssow mentioned the loss of cows in the Farmer and Stock Breeder Yearbook, 1907; the loss of horses fed on herbage cut from a hedge and containing M. perennis was recorded in the Journal of the Royal Agricultural Society in 1898; the loss of sheep was recorded by Henslow. As regards man, Ray records a case in which a family of five persons suffered severely from eating M. annua fried with bacon. Fishermen ate it with soup and all were seriously ill an hour later, with symptoms of irritant narcotic poisoning; two children died the next day. Cornevin saw M. annua used, after boiling, as a food for pigs, without ill consequences, in the east of France. This is believed to be due to the poison being volatile and destroyed by heat or boiling; hence in hay the plant is harmless, though Pott says that even in hay stock avoid it.

Toxic Principle. The poisonous properties are said to be due to Mercurialine, Oil of Euphorbia, a volatile toxic alkaloid. Esser states that the stem and leaves of M. annua contain Trimethylamine, which may perhaps be a decomposition product of Choline, a poisonous base.

Symptoms. Both plants are emetic and dangerously purgative, causing irritant and narcotic symptoms. Veterinary observation has shown that the poison is cumulative, and that it is usually after the weed has formed part of the food for 7, 8, or 10 days that symptoms first appear. In the case recorded by Blackhurst (see above) the cows suffered from inflammation of the digestive tract, with severe purging and loss of blood. The secretion of milk entirely stopped. One cow died, but three recovered in about four days. The fifth was not convalescent for three weeks and then had a permanently curved and injured neck, the muscles being subsequently found rich in fibrous tissue, and the last three joints partially anchylosed. Rabbits were tested by feeding two on the leaves, two on the stems and roots, and two on the ground seeds mixed with oatmeal; the first two were unaffected, but the other four died in a few hours, showing drowsiness and suffering, while the post-mortem showed gastritis.

The digestive and urinary tracts are affected. There is indigestion with slight bloating, then colic of varying intensity, and at first diarrhoea which may give place later to constipation; hÆmaturia; micturition is frequent, painful, and the urine is blackish and bloody; dullness, weakness, loss of appetite and refusal of food; the heart beats very strongly, the pulse is rapid, and the mucous membrane of the eye is reddish-yellow in colour. There is no modification of respiration (Cornevin).

According to MÜller, however, the symptoms at first include constipation and later severe and bloody diarrhoea.

In cattle Pott states that M. annua causes inflammation of the stomach and intestines, bloody urine, paralysis of bladder, foetid diarrhoea, abortion, and bluish coloured milk deficient in fat. MÜller states that there is occasionally blood in the milk. According to Lander there is in cows excessive bloody purgation, cessation of lactation, temperature 105° F., pulse 90, and increased respiration. The illness is protracted over several weeks, the animals being comatose after the first symptoms.

Box (Buxus sempervirens L.). Farm live-stock may occasionally have the opportunity of browsing on box, or clippings may be thrown to them with other green herbage from gardens. Care should be taken that clippings are otherwise disposed of. All parts of the plant are bitter and have been proved to be poisonous. The bitter taste tends to prevent animals eating sufficient of the plant to cause serious injury. Pigs have died a day after eating the leaves. Horses also were killed by eating 750 grammes (1·6 lb.) of the foliage.

Toxic Principles. FaurÉ found in the bark and leaves of box the toxic alkaloid Buxine, but it was believed that there were other toxic substances, since analysis showed the leaves to be less rich in Buxine than the bark, while they are three times as active. Other substances occurring in box are Parabuxine, Buxinidine, and Parabuxinidine.

Symptoms. Small amounts have an emetic and purgative action; with average amounts, there are, in addition, nervous symptoms, lameness, muscular tremors, vertigo, then a period of coma. Large amounts cause death with intense abdominal pains, dysenteric flux, tenesmus, convulsions, respiratory and circulatory troubles.

Pigs are chiefly affected after eating the leaves, exhibiting great thirst, uncertain gait and delirium, while death occurs within twenty-four hours.

Pott gives the general symptoms as sickness, diarrhoea, giddiness, stupefaction, convulsive movements, and colic.

AMENTACEÆ.

The Oak (Quercus sp.). Injury to stock from the Oak has been due in the first place to the leaves, and in the second to the acorns. In regard to the leaves no injury appears to have been recorded in Britain, but Cornevin devotes attention only to poisoning by the leaves, which in special circumstances have caused serious accidents to animals which have eaten them. In France, cattle taken to the forests for grazing purposes browse on the young shoots and leaves of the oak, and after some days there arises a trouble long known as Mal de Brou or Maladie des Bois, which may end fatally, sometimes even in 24 hours (see Symptoms below). A case was also reported from Nebraska in 1903, ten head of cattle having apparently died from eating oak leaves, the trimmings from trees. The stomachs were full of the leaves, and the intestines had the appearance of being burned in places. There was no evidence of impaction. When the cut branches were removed no more cattle were lost.

Serious losses have been caused through the ingestion of acorns by young cattle not over about two years old, the years 1808, 1870, 1884, and 1900 being especially noteworthy in this respect. Cattle over three years old have seldom been affected, while sheep and pigs, if not immune to “acorn poisoning,” are but slightly affected. MÜller, however, states that horses, cattle, sheep, and goats are affected; 9 quarts (10 litres) taken in four days were sufficient to cause poisoning in the case of a bullock. It is believed by some observers that half-ripe acorns—e.g. acorns which may drop owing to drought—are more injurious than thoroughly ripened acorns.

Some authorities appear to be of the opinion that “acorn poisoning” is not actually poisoning, but a serious form of indigestion. If this be so the symptoms must be regarded as exceedingly severe. There is no doubt that “acorn poisoning” is not well understood, but a great deal has been observed and written on the subject, and there is clear evidence that acorns may reasonably be held to be poisonous. It must be pointed out, however, that the poisoning does not usually follow on the consumption of acorns in small quantities, but is commonly due to full meals of acorns taken in periods when there is a dearth of herbage. By proper preparation and storage acorns have been converted into a most useful food for horses, cattle and sheep (Jour. Bd. Agric., Sept. 1914 and Feb. 1916, and Leaflet No. 291 of the Bd. Agric., The Food Value of Acorns, Horse-Chestnuts and Beech Mast). In Germany it has been found that acorns fed to fowls caused diminished egg-laying, which finally ceased, while the yolks of eggs laid were discoloured a dirty brown (Jour. Bd. Agric., Dec. 1915, p. 902).

Toxic Principle. The facts as to acorn poisoning and oak-leaf poisoning are not clearly known, and the actual toxic substance is similarly not certainly known. It is probable, however, that it consists of Tannin, or substances which give rise to Tannin.

Symptoms. In relation to Maladie des Bois due to leaves, Cornevin gives the symptoms as loss of appetite; less (and more difficult) rumination; constipation, which increases; lying down, animals looking at their flank as in colic, followed by rising and attempts to urinate, with passing of rosy-coloured liquid in jets; loss of milk production, which may drop to nothing; fever, trembling, enfeebled condition.

Three or four days after the commencement of illness rumination is completely suspended; there is stamping of the feet, colic, retracted stomach, pulse hard, heart agitated, accelerated respiration, violent muscular shocks, and frequent urination. The urine is always dark in colour, but varies from clear red to dark black, nut-brown being usual. Cases are only serious when a foetid, frothy, and abundant dysentery succeeds constipation, in which case there is rapid emaciation and death.

Usually the course of the illness is not rapid; but occasionally there is immediate and bloody urination with violent colic and sometimes intestinal hÆmorrhage, death occurring in 24 hours.

In poisoning by acorns there is progressive wasting, entire loss of appetite, diarrhoea, discharge of an excessive quantity of pale urine, sore places inside the mouth, discharge from the nostrils, and also from the eyes, which are always sunken, giving the animal a peculiar haggard expression. There is no fever; on the contrary, the temperature is commonly below normal, though in some cases stated to be above normal.

MÜller remarks on the severe constipation, followed by dysenteric diarrhoea, caused by acorns, especially when eaten in the half-ripe condition, horses, cattle, sheep, and goats being affected.

The experimental poisoning of a young steer and a young sheep by fully ripe acorns was described in 1871 (Jour. R.A.S.E., 1871). In the steer the symptoms were a semi-conscious condition, weak pulse, pallid membranes, cold surface of body, torpid bowels, slow breathing, twitchings of muscles, and a disposition to maintain a recumbent position. Inflammation was entirely absent. The symptoms increased in severity day by day; there ensued a copious flow of colourless urine; a mucopurulent discharge from the eyes and nostrils. No impairment of health followed the feeding of acorns to the sheep.

Thorburn (Veterinary Journal, Feb., 1902) mentions loss of appetite, grunting, disinclination to move, prostration, icy coldness of extremities, very rapid emaciation (this sometimes was particularly noticeable), pulse very small and weak (in some cases almost imperceptible), temperature high (105° to 107° F.,) and constipation succeeded by watery diarrhoea.

Brookes and Yeomans described (Veterinary Journal, 1912) an instance in which 30 animals were affected and 9 died. The chief symptoms were a dull and depressed appearance, entire absence of appetite and rumination, a weak feeble pulse, subnormal temperature and disinclination to move. Three cases showed a mucous and blood-tinged discharge from the nostrils and anus, and these all died, one eight days after being seen and the other two the day afterwards. Obstinate stoppage was noticeable in all cases, and the fÆces were inky black, stinking and very thick. Yeomans observed similar symptoms of acute digestive disturbance; later the eyes had a sunken appearance, diarrhoea set in, the fÆces being dark coloured, offensive and bloodstained. The temperature was at first normal and later subnormal, and in fatal cases death took place in from 3 to 7 days.

CONIFERÆ.

The only Conifer which commonly causes poisoning of live-stock is the Yew, but injury might more frequently occur were it not for the fact that Conifers generally are unpleasant to the taste, and are hence avoided by stock. Many species, however, contain Tannin, Resins and Gums, Volatile Oils, and an acrid substance which may cause inflammation of the digestive and urinary tracts, while Tanret found in the young shoots of Picea the bitter glucoside Picein (C₁₄H₁₈O₇H₂O); Kawalier and Thal found the intensely bitter glucoside Pinipicrin (C₂₂H₃₆O₁₁) in Pinus sylvestris, Thuja occidentalis and Juniperus Sabina; and Kubel isolated Coniferin or Abietin (C₁₆H₂₂O₈), a slightly bitter glucoside found in Abies excelsa, A. pectinata, Pinus strobus, Larix europÆa and other conifers. It is not clear, however, whether these substances are at all poisonous. It is quite possible that if eaten in quantity the foliage of some Conifers may induce poisonous symptoms and even death in the animals concerned. It is noteworthy, however, that according to Pott the needles of Picea excelsa, Abies pectinata, Larix europÆa, and Pinus sp. are, in the mountainous districts of Steiermark, KÄrnten, and Tyrol, extensively fed to cattle and sheep, usually as a supplementary food, either fresh or dried and ground up—chiefly perhaps as an appetiser, and in small quantities as a dietetic; Juniperus sp. are similarly utilised in some districts. It is not known to what extent the foliage may be fed without harmful consequences, but Pott states that large quantities can cause hÆmaturia and similar effects, and hence only small quantities should be used, and even so may impart a bad flavour to the milk of cows. All green needles frequently cause digestive troubles.

A case has recently (January, 1916) been reported to the author in which a Douglas Fir was cut down and a small branch about 4 ft. long was flung over into a field. Two sheep nipped off the bark and nearly died, but both vomited and recovered. The farmer reporting this experience recalls that over 30 years ago, after a gale, a lot of trees were blown down in a small plantation, and in severe weather the sheep ate the bark to such an extent that 80 of them aborted, while of the ewes which did not eat the bark none aborted, so that it would appear that the bark of Scotch Fir and Spruce was to blame for the loss.

The foliage of the Yew (see below) is well known to be dangerously poisonous to stock, and has caused many losses.

In regard to Cupressus the only cases of poisoning which have been traced are recorded in The Journal of the Board of Agriculture (October, 1905). These cases were reported as follows:—

“Two instances have recently come before the Board in which the death of cattle has been attributed to the poisonous effects of Cupressus macrocarpa and C. nootkatensis. In one case four bullocks died, and on the internal organs being forwarded by the owner to the Royal Veterinary College, Professor McFadyean reported that from the inflamed condition of the fourth stomach and from the description of the symptoms he had little doubt that the cause of death was irritant poison. Some pieces of Cupressus macrocarpa were found in their stomachs, and in default of any other explanation it was suggested that this plant might have some poisonous properties.

“In another case three heifers are stated to have suffered from irritant poison; one of them died, but the other two recovered on removal to another field. The veterinary surgeon in this case also attributed the death to a Cupressus (C. nootkatensis) growing by the side of the field.

“The Board have no information as to the poisonous properties of these two species, nor can any record be found of any similar case which would tend to confirm the suspicion that they are poisonous to cattle.”

Yew (Taxus baccata L.). As stated above, the Yew is the only British conifer that is likely to prove seriously poisonous to live stock. It has unfortunately caused the death of many horses and cattle, while asses, mules, deer, pigs, rabbits, and pheasants have also been poisoned. Many cases of fatal human poisoning have also occurred. For example, the poisoning of a horse, and of cattle, horses, and deer were mentioned respectively in 1885 and 1893 (Jour. Roy. Agric. Soc.). “Through eating the poisonous leaves of a Yew tree, four cross-bred cattle were found dead in a shrubbery at Elmswell, near Driffield” (Daily Mail, 13th Dec., 1913). Many cases of poisoning and death of animals due to eating the foliage direct from the trees have been recorded in the veterinary journals—e.g. the death of 15 cattle in The Veterinary News, 7th Dec., 1912. Tegetmeier recorded the death of pheasants due to Yew leaves and seeds (The Field, 11th Nov., 1893). On the other hand many cases have been recorded in which fatal results have not followed the ingestion of the leaves, and it appears that the lower branches of Yew trees in parks are constantly cropped by cattle without ill effects. (Trans. Chem. Soc., 1902; Jour. Bd. Agric., 1903).

The bark, leaves, and seeds are all poisonous, the leaves usually being the parts eaten. Henslow states that of 32 cases of Yew poisoning 9 were due to the berries and the remainder to the leaves, while 20 of the 32 cases were fatal. In 1879 R. Modlen published a circumstantial account of children poisoned at Oxford by the fruits, and demonstrated that the arillus or scarlet mucilaginous cup surrounding the ripe seed is not poisonous, but that the seeds are so. Apart from idiosyncrasy of appetite stock are perhaps more likely to eat the dark green foliage of the Yew in winter or during scarcity of green fodder than at other times. The old leaves or shoots are the most poisonous parts.

By experiments with autumn and winter leaves Cornevin found that the following quantities would be necessary to kill various animals:—

Other authorities, however, quote much lower quantities as necessary to kill the horse and ox, and Pott says that in the case of horses 150 to 180 grammes (0·33 to 0·4 lb.) is sufficient to cause death in one-quarter to one-half an hour, without previous symptoms. Eaten by an animal on a full stomach a small quantity of Yew may cause little or no dangerous results.

Toxic Principle. The researches of MarmÉ pointed to the alkaloid Taxine (C₃₇H₅₂NO₁₀) as the toxic substance. Later investigations of Thorpe and Stubbs confirmed this view, and it is generally agreed that this substance is the toxic principle, though doubts as to its being the only poison have been expressed. Taxine has a bitter taste, is a heart depressant, and may cause death from suffocation. The yew also contains a considerable quantity of Formic Acid, and the acrid, irritant volatile Oil of Yew.

Thorpe and Stubbs (Trans. Chem. Soc., 1902) found in the fresh leaves of the common Yew from 0·1 to 0·18 per cent. of Taxine. In an investigation of the Irish Yew (T. baccata var. fastigiata) Moss found Taxine present as follows:—

In the leaves of the male common Yew Moss found 0·082 per cent. of Taxine, or less than one-half the quantity found by Thorpe and Stubbs.

Symptoms. The Yew is irritant and narcotic, and the poison is not cumulative, but on the other hand rapidly effective, so that animals may die apparently suddenly, no previous symptoms having been observed.

When small quantities only have been taken the closest attention is necessary to discern the symptoms, which simply consist in a little excitement with a slight rise in temperature.

With larger (but not fatal) quantities the first symptom, excitement, is more pronounced and is followed by nausea, and (where possible) vomiting. There is a pronounced slackening of respiration and circulation, the pulse being small, slow, and difficult to perceive, and the movement of the flanks very slow; sensibility is diminished. There is a fall in temperature, the skin and extremities being cold. The head is lowered, the eyes are closed and there is decubitus. In some cases pregnant animals have aborted. In the horse there are muscular tremors and frequent urination. In cattle and sheep rumination is suspended and there is more or less pronounced tympanites, with eructation, nausea, and sometimes vomiting. Pigs bury the head in the litter and sleep, their sleep being interrupted from time to time by nausea and groaning; or the animals rise, stagger about, and lie down again.

With fatal quantities the foregoing symptoms may be followed by coma, with death in two hours or more after the poisoning, but more generally and usually in horses, asses, and mules (but also in cattle) there is no period of coma, the excitement is less pronounced and often unobserved, and death appears very sudden. The animals stop, shake their heads, respiration is modified, there is falling, and death (sometimes with convulsions) results from cessation of the heart’s action (Cornevin).

The symptoms given by MÜller are roaring, torpidity, stupefaction, laboured breathing, convulsions and death in from ten minutes to an hour in the worst cases; or where the course of poisoning is slower, there is salivation, nausea, vomiting, bloating, retardation of pulse and respiration, great giddiness and stupefaction, diabetes and hÆmaturia.

The rapidity of the poisoning is confirmed by cases noted in the veterinary journals. Lander shows that the effects often only appear in cattle when chewing the cud; whilst quietly chewing, they drop as if shot. In some examples the animal died while eating the plant, or was found to have fallen and died suddenly and without evidence of a struggle. The animal in some cases will stop suddenly whilst working, start blowing and trembling, stagger, fall on its haunches, then on its side, and die quietly. Death occurs in about five minutes with symptoms resembling apoplexy. A colt died after 16 or 17 hours; the plant was taken on a full stomach, but paralysis of the alimentary system with stoppage of digestion immediately ensued.

In the case of pheasants there was acute inflammation of the small intestines (Tegetmeier).

Cuckoo Pint (Arum maculatum L.). The well-known Cuckoo Pint, or Lords and Ladies, is to be regarded as highly poisonous, and children have died from eating the berries. Animals have exceptionally eaten the plant, but no record of death has been found, as it does not appear to be taken in sufficient quantity. Cornevin records that pigs have eaten the roots, and suffered in consequence, though the results were not fatal. All parts of the plant are poisonous, though the virulence is lost on drying. The plant is acrid, and emits a disagreeable smell when bruised. In Gerarde’s Herball the following passage occurs: “The most pure and white starch is made from the rootes of the Cuckowpint; but most hurtfull for the hands of the laundresse that hath the handling of it, for it choppeth, blistereth, and maketh the hands rough and rugged, and withall smarting.” In Dorset the tuber-like corms have been macerated in water, dried and powdered, and eaten under the name Portland Sago or Portland Arrowroot, the poisonous property being dissipated.

Toxic Principle. The Cuckoo Pint does not seem to have received much attention in this connection, but the poisonous principle is believed to be a Saponin.

Symptoms. The juice acts as an irritant when in contact with the mucous membrane. When a pig has eaten several roots rich in sap, the mouth and tongue redden and tumefy, there is salivation, and swallowing is difficult on account of the inflammation at the back of the mouth. Introduced in small quantity into the digestive tract it acts as an irritant and purgative, and sometimes causes vomiting. Severe intestinal pains, excitement, some muscular contraction of the limbs, rocking of the head, and superpurgation with tenesmus are also symptoms which have been observed. The intestinal pains continue for some days and the appetite is small. Cornevin states that animals never take a sufficient quantity to cause fatal poisoning, but according to Lander, if a dangerous quantity is taken, convulsions, exhaustion, and death from shock may possibly follow the foregoing symptoms.

A case in which a horse was poisoned through a wound being washed with a decoction of arum leaves is cited by MÜller. There was much local swelling, trembling, and rapid breathing, and the heart beat strongly; the animal died on the third day.