The Ungulate order has been variously divided by zoologists, and is still said to be composed of two main sections, even-toed and odd-toed Ungulates, with the addition of a good many “outsiders” if one may use the term.

These sections form two sub-orders, and the division suits my purpose here very well. I take the odd-toed sub-order of the Ungulata Vera first.

Lessons from the Domestic Horse.

The domestic horse is the only member of this section that requires detailed attention, and its value for studying the direction of the mammalian hair is great, on account of the immense number of specimens available, the quality and varied distribu­tion of its hair, the size of the animal, and, most of all, our intimate knowledge of its habits of life for many thousands of years.

Many volumes have been written by man about this, his best and second oldest friend among lower animals. His ancestry, his story as servant of man, his virtues, strength, speed, intelligence, his use for war and peace, his colour, varieties of breed and money value; his anatomy, physiology, pathology, his medicine and surgery have all been written by many able men. Indeed before the great revela­tion of what man can be and do that the great war has given us, many observers of mankind were prepared to adapt the saying of a French cynic and to declare: “The more I see of men the better I like horses.” Swift at any rate came near this in his bitter account of a voyage to the Houyhnhnms, which lasted sixteen years and seven months, towards the end of which he said: “For who can read of the virtues I have mentioned in the glorious Houyhnhnms without being ashamed of his own vices, when he considers himself as the reasoning governing animal of his country?” But in all these writings, even in that last striking book by Mr. Roger Pocock, Horses, little or no attention is given to the patterns of its coat from the point of view of science. I remember reading a paper on this subject many years ago before a distinguished company of veterinary surgeons, and though they had glanced at these patterns in a passing way, as peculiarities, no real knowledge of them nor attempt to understand them was shown by this body of experts. They were too “practical” for this view of things. I may remark here that many of the most vocal and active among us, and especially the Germans, have been overmuch disposed to study science ad hoc, for its commercial and military value, though here, as elsewhere one must be tolerant and each follow his own taste, seeking light, more light. One must live and let live.

The horse does his work coram publico in every street of every town, in fields, roads and race-courses, and displays on his hairy coat some graceful patterns which are at the same time subjects for scientific inquiry, and brands of his long servitude to man. I have examined many thousands of horses in some twenty years with never failing interest. Belonging to the large family of EquidÆ, including asses, zebras and quaggas, he is the most highly-developed of them all. His habits first, and then the most notable of his hair-patterns must now be considered.

Some Habits of the Horse.

He has few habits which bear on the present subject, and of these his active habits of locomo­tion are far the most important. He has his share of passive habits, for he stands many hours a day, and often sleeps standing, and he does his share in lying down, though Mr. Roger Pocock says he takes no more than four hours’ sleep in this attitude. His rule in lying down is to “lie anyhow,” if one may so describe it, and thus his two passive attitudes of standing and lying, have little or no bearing on the questions before us. His glory is in his gallop, canter, trot and walk. His business is indeed a going concern in more than one sense, perhaps in three. The world is moving fast in its old age, and some men are calculating how long it may take for him to become as nearly extinct as the quagga.

With the clue given to this inquiry in Chapter VI. we need have little difficulty in tracing the manner in which his locomotive life, ancestral and personal, is engraved on his hairy coat. We shall bear in mind the primitive direction of his hair, hair-streams, lines of least resistance, and the powerful forces of underlying traction of muscles, opposed or divergent.

It is, of course, most convenient to examine a specimen with a fine, short coat rather than one with its wild and more shaggy hair remaining.

The two regions where the play of great forces comes most powerfully into action during locomo­tion are round about the elbow-joint (which we should be disposed to call the shoulder) and the hip-joint, in which regions the range of extension and flexion, as well as the number of muscles engaged, is much greater than at any other part of the limbs. It is in the neighbourhood of these two regions that the most characteristic of all the patterns of hair are found, and the names given to the patterns (whorls, featherings and crests) in these critical areas are Pectoral (Fig.30) and Inguinal (see Fig.31) with a third (G, H, I, Fig.31) which is called Axillary, and is not constantly present. The main muscles involved in Figs.30, 31 are shown in Fig.33. The Frontal (Fig.32) is another of the critical areas, indirectly concerned in locomo­tion, and will be considered first.

The Frontal pattern forms the star on a horse’s forehead, often very noticeable when the hair of it is white. No detailed descrip­tion is required if the illustra­tion of it in Fig.32 be studied. It is enough to point out that it lies at or very near the level of the eyes, sometimes a little above and sometimes a little below this, and there is occasionally a double whorl, the second lying above the normal one.

Fig. 32A shows the muscles of the fronto-nasal region of the horse and the manner in which the skin of this central region is pulled upon in divergent and opposing directions, by a long muscle, called the Maxillaris, downwards and outwards, by a small thick muscle, the Corrugator, inwards, by a deeper and more oblique muscle, the Nasalis, downwards and inwards, and a little more remotely by the Temporal muscle, and the intrinsic muscles of the mobile ears. There are thus at least five muscles on each side, all pulling more or less against one another on this much-disturbed area of skin. The struggle has been long ago given up and a compromise arrived at which is registered in the frontal pattern.

Now if anyone doubts whether these comparatively small muscles act often or strongly enough to produce effects on the hair over them he need only consult Mr. Roger Pocock’s book to understand the story of this battle of small forces and its result on the hair.

In his wild state the horse is dependent to a remarkable degree to his sense of smell for his safety from foes (Pocock), and very much less so on his sight. Indeed that writer says his range of good vision is about six yards. At that range his sight is of great value to him for protec­tion from certain of the dangers of his life, and we see in a domestic horse to-day the evidence of his past wild life by his rapid and keen glances at objects at the sides of the road, both when we ride and drive him. His corrugator muscle must be almost constantly in action. But his sense of smell is the sling and stone with which he encounters his Goliaths before they can get near him, and he ceaselessly expands and draws up his flexible nostrils employing his nasalis and his maxillaris for snuffing the air. He has also much useful protec­tion from his sense of hearing and we all know how those mobile ears of his are hardly ever at rest, pointing now forwards, now backwards, and again outwards, as he goes on his way. The degree of these movements is largely a matter of individual character and breeding. The case for a conflict of forces in this region is, I submit, fully made out, and it is easy to see that a radiating pattern of hair, such as there is in the simple whorl, is only the natural outcome of all this complex muscular action. The extension of the whorl upwards in the shape of a feathering which is sufficiently common, indicates that the struggle has been carried beyond the original battle-field by the muscles of the ears.

The pectoral (Fig.30) pattern lies over the great fleshy masses formed by the pectoral muscles, which draw the fore-limbs upwards and inwards in conjunc­tion with others in the actions of flexion and extension of these limbs. The patterns, A.B.C., are wide expansions of reversed hair beginning in the whorl (A), extending (B) upwards and terminated in a crest (C). This pattern is, like the frontal, invariably present in a domestic horse, and is shared by many other ungulates such as deer and antelopes, as mentioned in the appendix of a small book49, I published in 1901. But in none is it so striking or definite as in the horse. The contractions of these pectoral muscles and their jolt at each step are easily observed in a trotting horse. It is interesting to compare this pattern on the horse’s pectoral region with what is found on the closely allied ass and mule. In the horse it is long and wide and never absent, and is especially well-developed in high-stepping horses whether cart-horses or others selected because of their high action in trotting. Its size, indeed, is a measure of the activity of the pectoral muscles and flexors of the fore-limb. In the ass it is often absent, and, when it is present, it is rudimentary; in the mule it is more frequently present than in the ass, but does not approach the pattern of the horse for size. These degrees of development in horse, ass and mule correspond closely with the locomotive habits of the three animals.

The inguinal (Fig.31) pattern is one which the most casual observer of a horse cannot fail to notice, and it is so graceful in its shape as to add to the many beauties of its possessor. But in spite of this no breeder of horses has ever taken this pattern as one of the “points” of the animal, so that here again selection, even of the artificial kind, has had no share in its development. It is but a by-product of the locomotive life of the horse, and a very ancient character, for it is present in Przewalski’s horse, a probable ancestor of Equus Caballus. A domestic horse without this pattern would be a freak of Nature. It occurs in equus hemionus, the Thibetan wild ass, but not in zebras or in the quagga.

The inguinal pattern deserves rather more descrip­tion than the two others. It is shown in Fig.31 as A.B.C. and the muscles which produce it and govern its development are shown in Fig.33. It starts in a whorl (A) at the fold of skin which passes from the lower part of the abdomen to the hind limb. This radiates and expands into a bilateral and symmetrical expansion shaped like the barbs of a feather. This proceeds upwards in the inguinal hollow in a direction which curves gently with the concavity forwards, dividing the trunk of the animal from the great rounded mass of muscle forming the hind quarters. It extends upwards to the level of the iliac crest where a projec­tion covered by muscles can always be recognised, and over this “iliac crest” of the anatomist it terminates abruptly in a ridge or crest of its own, lying parallel with the long axis of the trunk. It is very pretty to see above it the hair-streams from the back of the animal breaking away like two currents of water on either side of an outstanding rock, the anterior passing with a wide curve forwards and downwards along the flank and the hinder one losing itself more gradually in the original course of the hair-streams of the hind-quarters. No illustra­tion or verbal descrip­tion gives so good a picture as one can get from inspec­tion of the smooth coat of any well-developed domestic horse.

When a few trotting horses are watched by an observer who bears in mind the accompanying pictures of the muscles and the inguinal pattern it can be seen at once how all the conditions are present for fulfilling a gradual change from a primitive slope of hair to these highly-developed patterns, if he has also followed the conclusion reached in Chapter I. that muscular action can change the direction of hair in the individual. If at the same time the degree and extent of the jolt which occurs here at every step be noted, it is seen to be sharply limited to the area covered by this pattern, and ceasing, as it does, abruptly and significantly at the level of the iliac crest. The forward range of the jolt, easily seen in a thin horse, is much wider than the backward, and marks out very closely the extent of the forward curve taken by the anterior hair-stream as it descends from the crest. One may also remark that there is a small but interesting point which one can see during or after a shower of rain, for then the flank of a horse presents a curious distribu­tion of the moisture. At the very point where the forward stream joins the main stream from the thorax and abdomen a definite line of darker moist hair is to be seen and the moist-looking surface is limited to the stream of the trunk and separated from that of the flank. This line of demarca­tion clearly indicates the place where the forward jolt terminates during rapid movement.

The Domestic Ass and Mule.

There are two closely related animals, the domestic ass and the mule, which ought to show this inguinal pattern if affinity and variation could be fairly invoked to account for it on the theory of selection. These are also animals whose mode of life is locomotive, but in a much less degree than the horse and their paces are quieter and less free in character. What then is found in them as to the size or persistence of this pattern? In the ass it is absent or nearly so (I have found one example of its presence), and in the mule it is variable and never occupies more than half the area of that in the horse. These facts agree closely with the hybrid character of the mule and the differing activities of the horse, mule and ass. The pattern in Przewalski’s horse is small and oval and resembles that of the mule. The onager (equus asinus), which is very much like these three domestic animals in form, has an inguinal pattern, much less in size indeed than that of the horse, but well-defined, and this fact is in keeping with its character for remarkable fleetness of foot and activity. The three zebras, Mountain, Grevy’s and Burchell’s, show no inguinal pattern, in spite of their power of rapid locomo­tion and resemblance in size and form to the horse. Though they have that power they exercise it in their wild lives for their own sakes alone, in the intermittent way which is bound up with their habit of life, and not for the sake of man, as in the case of the horse.

The pectoral and inguinal regions of the domestic horse are two of the most valuable fields in the mammalian body for studying the formation by muscular action of patterns of hair, for this animal is the locomotive animal par excellence. Here the process has been carried to the extreme limit, and these two are prominent examples among the characters to which I drew attention in a paper published in the Proceedings of the Zoological Society of London, “On proposed additions to the accepted systematic characters of certain Mammals,” June 9th, 1904, Vol.I. I am still of the opinion that they deserve “Flag rank,” though they have not yet been promoted. Be that as it may I think it may be well here to compare two animals belonging to the family EquidÆ, the horse and zebra, which resemble one another very closely in form—in respect of these patterns.

Horse and Zebra Compared.

If a horse of the hackney type and a zebra were skinned and the bodies of the two animals then examined I suppose a competent anatomist would find some difficulty in distinguishing one from the other so closely do these two allied species of equidÆ, one wild and the other domesticated, resemble one another in structure. But in this as in many other questions form is not to be considered alone. The coloura­tion of the two animals is strikingly different, but, in its humble way, the difference of their patterns of hair-arrangement is worthy of notice. The horse in different specimens chosen from a large group will exhibit patterns in the frontal, pectoral and inguinal regions constantly, and variably in less common regions, axillary, cervical and gluteal, that is to say, in six different areas. I have examined many zebras, living and dead, and find no constant pattern in the whole of its large surface of skin except an ill-developed frontal and a very small cervical one—two in all. The mere numerical difference is not the only important one, for the insignificance of the size of the two zebra patterns and the constancy and high development of many of those of the horse are not less significant from the present point of view. I submit that these two animals carry about with them on their hairy coats indubitable records of their personal and ancestral habits. Attention to the facts of a horse’s life and certain related and contrasted facts of the lives of other animals, of which the zebra may be taken as a type, will show the reasons why these patterns are to be looked upon as registers of long-past and present activities of the species concerned. The horse has been developed out of a wild plastic stock with some such ancestors as the wild horse of Przewalski, lately brought to Europe, by a process of selection by man during a thousand generations, first in its Central Asian cradle and later all over the civilized world. It has been as much made by man for his purposes in locomo­tion as a locomotive engine has been made by him. The one has been produced in accordance with the laws of applied physics and the other by those of biology. His locomotive life has come to pass for the needs of higher, or at any rate more cunning creatures, who have availed themselves of the potentialities provided by Nature. The zebra in its habits differs from the horse in the simple, but fundamental point that the former lives the ordinary active life of a wild animal for its own needs of protec­tion against foes and search for food, the latter has not only this activity of life in its organisa­tion, but has, super-added to it by domestica­tion, all the locomotive life of a beast of burden. The zebra presents few, if any, of those phenomena which I have often termed Animal Pedometers,50 so characteristic of the hairy coat of the horse I am reverting here again to the region of metaphor for which I offer no excuse, but only a few remarks as to the use and value of that elusive method of illustra­tion. Metaphor is a figure of speech or writing which consists in a transference of thought from one idea to another. It is, therefore, not a simple substitu­tion of synonymous expressions, nor is it merely a simile. It is in hourly use in the speech and writing of common as well as highly educated persons, and adds much to the ease of communica­tion among us of our thoughts upon subjects which rise somewhat above the level of mere statement of obvious facts. So long as metaphors are not abused by being used as arguments to prove some proposi­tion, but only as illustrations of our meaning, we gain greatly by their legitimate use. It is not for nothing the well-drilled Press of Germany in their journals and its histrionic Emperor in his rhetorical outbursts, make extensive use of metaphors. We are everlastingly reading of Germany’s “biological necessity,” her “iron will to victory,” the “steel ring of field-grey heroes who guard her against a world of devils,” of her “brilliant second,” her “granite walls,” her “future on the water,” the “Admiral of the Atlantic,” “grasping the trident,” and so on in nearly every public utterance of her leaders. They know well their audience and employ these harmless, if often ridiculous, expressions with a definite and legitimate purpose, and are well qualified for creating the public opinion of a nation that dearly loves a phrase.

Well, this term, Animal Pedometers, is used here not for proving anything, but for the purpose of impressing on the mind of the reader the fact of certain patterns on the horse’s skin being intimately related to its locomotive life which, I hope I may assume, has been sufficiently demonstrated in this chapter. A pedometer is one of those works of men devised for his physical and mental advancement which are marked by a precision as well as purpose often absent from Nature’s handiwork. Just as a pedestrian, cyclist, or motorist carries with him his pedometer and tells you with some pride the number of miles he has “done” in a day or hour, so the horse displays urbÉ et orbi his rougher registers of the locomotive triumphs of his ancestors and himself, and these I call Animal Pedometers by way of metaphor, and patterns by way of fact.

The less striking and rarer patterns of the horse’s hair have been fully described elsewhere,51 and it would serve no useful end to refer to them at length, nor to multiply proofs of the position here maintained.