1 The term Chorology, used by Haeckel, nearly covers the ground.

2 Ontos-gennao (individual-making, or genesis of the individual).

3 Taxis, nomos (relating to science of arrangement).

4 This statement is general; it will be modified hereafter.

5 Phule-gennao (kind-making); genesis of the race.

6 This formulation of the laws of organic succession was given by me in 1860, before I knew anything of either Darwin’s or Spencer’s evolution. They were my own mode of formulating Agassiz’s views.

7 Genesis without previous life—spontaneous generation.

8 Fishes were first introduced in the later Silurian; but became dominant in the Devonian.

9 Amphibians were introduced in the Carboniferous, but true reptile not until the Permian.

10 Of course I mean downward in social function. Individually the scavenger may be nobler than the statesman.

11 Cope, “Science,” vol. ii, p. 274, 1883.

12 Boston Society of Natural History—anniversary memoir, 1880. Also, “American Naturalist,” June, 1882.

13 “Archives des Sciences,” vol. liv, 1875.

14 “Nature,” vol. xxxi, p. 4, 1884.

15 See abstract of Dr. Romanes’s views, “Nature,” vol. xxxiv, pp. 314, 336, 362. Also, discussions of the same by Meldola, Galton, Wallace, etc., in immediately subsequent numbers.

16 This subject is more fully treated in chapter IX, p. 240 et seq.

17 See an article entitled “Genesis of Sex,” “Popular Science Monthly,” 1879, vol. xvi, p. 167.

18 Mr. Wallace has recently, in his work on “Darwinism,” taken strong ground against this Darwinian factor. He thinks, for example, that sexual vigor is the cause of both the splendor of color and the pertinacity which secures the female. We see little difference in this way of putting it. Our object, however, is not to argue the question of what are true factors, but simply to give the most accepted, and, as it seems to us, also the most probable view.

19 By reason I mean the faculty of dealing with the phenomena of the inner world of consciousness and ideas. Animals live in one world—the outer world of sense; man in two—the outer world of sense, like animals, but also in an inner and higher world of ideas. All that is characteristic of man comes of this capacity of dealing with the inner world. In default of a better word I call it reason. If any one can suggest a better word, I will gladly adopt it.

20 While all comparative anatomists agree that the lung is a diverticulum from the oesophagus, like the air-bladder of the gar-fish, some think that it is a different diverticulum, which is seen first in the dipnoi.

21 Undoubtedly the true principle on which primary groups ought to be made is, identity of general plan of structure, or traceableness of homology throughout. For these groups are the great primary branches of the tree of life, and classification ought to represent degrees of genetic relationship. This was Agassiz’s principle, although he did not admit the genetic relation. This principle has been, it seems to us, too much neglected by later systematists.

22 The Amphioxus, the lowest of all vertebrates—if vertebrate it may be called—is an exception to 2 and 3. In this animal the vertebrate type is not yet fully declared.

23 This is only one example under a general law which it may be well to stop a moment to illustrate. A repetition of similar parts performing the same function is always an evidence of low organization, and as we rise in the scale of organization such parts usually become fewer and more efficient. Thus, to give one example, myriapods, as their name indicates, have hundreds of locomotive organs—lower crustaceans perhaps thirty or forty. As we go up, they are reduced to fourteen (tetradecapods), then to ten (decapods), then in spiders to eight, in insects to six, in vertebrates to four, and in man to two. A similar reduction in number, but increase in efficiency, is found in toes, when they are used for support and locomotion only. In man we find the normal number of five (1), because his hands are used for grasping and the functions of the fingers are not the same; and (2), because man’s development was almost wholly brainward. In other respects his structure is far less specialized than most other mammals. He can not compete with carnivores in strength and ferocity, nor with herbivores in fleetness. In the struggle for life, therefore, there was nothing left for him but increase in intelligence. Probably four is the smallest number of locomotive organs consistent with highest efficiency. In retaining but two legs for locomotion, man has lost in locomotive efficiency, but by the sacrifice he liberates two limbs for higher functions.

24 “Proceedings of American Academy of Arts and Sciences,” vol. xiv, May, 1878.

25 Fol., “Archives des Sciences,” vol. xiv, p. 84, 1885; “Science,” vol. vi, p. 92, 1885.

26 Of course, this is a purely imaginary case. The conditions of development of the eggs of higher animals forbid continuous watching the process. Yet we do observe in different individuals all these stages in mammals as well as other animals.

27 These baleen plates are not modifications of teeth, as might at first be supposed, but rather of the transverse gum-ridges found on the roof of the mouth of many mammals, and conspicuous in the horse.

28 “Proceedings of the California Academy of Science,” vol. v, p. 152. 1873.

29 For fuller discussion of this subject, see “Bulletin of the California Academy of Science,” No. 8, 1887, and “American Journal of Science,” for Dec., 1887.

30 “Origin of Races of the Dog.” “Annals and Magazine of Natural History,” vol. xvii, p. 295. 1886.

31 Mr. Galton (“Nature,” August 26, 1886) has used a diagram similar to the above (which I first used in 1879) to illustrate the law of sexual attraction and repugnance.

32 This subject is more fully discussed by the author in an article entitled “Genesis of Sex,” in “The Popular Science Monthly,” vol. xvi, p. 167, 1879.

33 For examples of this the reader is referred to Cope, “Bulletin of the National Museum,” No. 1; and to Coues’s “Key to North American Birds,” last edition.

34 “Monatsbericht d. k. Preuss. Akademie d. Wissenschaft zu Berlin,” for July, 1866.

35 “Genesis of Tertiary Species of Planorbis at Steinheim.” A. Hyatt, Anniversary Memoir of the Boston Society of Natural History, 1880.

36 In a letter to the author, dated February 13, 1887, Prof. Cope says: “Such transitions of species are clearly indicated in the OreodontidÆ, where such different forms as O. gracilis and O. Culbertsoni are connected by intergradations.”

37 “American Naturalist,” 1873; “Popular Science Monthly,” June, 1873.

38 For a fuller development of this subject the reader is referred to an article by the author, entitled “Critical Periods in the History of, and their Relation to, Evolution” (“American Journal of Science,” vol. xiv, p. 99, 1877).

39 “Reflex Action and Theism,” William James, “Unitarian Review” for November, 1881.

40 See an article by the author on this subject, “American Journal of Science,” series ii, vol. xxviii, p. 305, 1859, and in “Popular Science Monthly,” vol. iv, p. 156, 1873.

41 All chemical compounds are dissociated by sufficient heat.

42 The origin of vital from chemical force in the green leaves of plants can not be doubted; but this does not, of course, explain the mystery of the first origin of life on the earth, for one condition of the change now is the contact of living matter.

43 I know it is the fashion to ridicule the use of the terms vitality, vital force, as a remnant of an old superstition; and yet the same men who do so use the terms gravity, electricity, chemical force, etc. Vital force is indeed correlated with other forces of Nature, but is none the less a distinct form of force, far more distinct than any other unless it be the still higher form of psychical, and therefore it better deserves a distinct name than any lower form. Each form of force gives rise to a peculiar group of phenomena, and the study of these to a special department of science. Now, the group of phenomena called vital is more peculiar, more different from other groups than these are from each other, and the science of physiology is a more distinct department than either physics or chemistry, and therefore the form of force, which determines these phenomena, is more distinct and better entitled to a name than any physical or chemical force.

44 “Princeton Review” for May, 1884.

45 “Popular Science Monthly,” December, 1873.

46 For a fuller statement of this antithesis, see an article by the author entitled “Evolution in Relation to Materialism,” “Princeton Review,” for March, 1881.

47 Johnstone Stoney, “Nature,” vol. xxxi, p. 422.

48 “Nature,” vol. xxxiv, p. 385. 1886.

49 So, again, see a book recently published (“Nature,” vol. xliii, p. 460, 1891), entitled “Whence comes Man, from Nature or from God?” The answer is plain. From both—from God through Nature. Evolution is the method of creation.