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additions were inadequate when the great multitude of animals was realized.

Difficulty also arose over the question of creation. Aquinas said "Nothing was made by God, after the six days of creation, absolutely new, but it was in some sense included in the work of the six days," and that " even new species, if any appear, have existed before in certain native properties, just as animals are produced from putrefaction." 20 It did not escape observation that there were two not altogether harmonious accounts in Genesis. In the first (Gen. 1:20) it is stated that the waters bring forth fishes, marine animals and birds, while in the second (Gen. 2:19) it is stated that land animals and birds were created from the ground. John Lightfoot tried to reconcile another divergence in the accounts by saying that of the "clean sort of beasts there were seven of every kind created, three couples for breeding and the odd one for Adam's sacrifice on his fall, which God foresaw; " of unclean beasts only one couple. 21 These divergencies caused little trouble - the real question lay in the supposed immutability of species each of which appeared at the time of the creation and remained unchanged. Yet there was as has been indicated a general belief in the spontaneous generation of types more or less insignificant. The decision was in favor of permanency.

Francis Bacon (1561-1626) expressed a doubt as to the fixity of species and asked if the changes that had apparently taken place could be due to the accumulated effects of variations. Bacon was the first of a series of great men, which included Descartes, Leibnitz, Kant, Lessing, and Schelling who broke away from the old moorings. By emphasizing variation, they paved the way for the theory of evolution. In the eighteenth century the Benedictine Dom Calmet in his commentary suggests that all the species of one genus had originally been one species. This idea was accepted in part by Linnæus.

20 WHITE, A. D. о. с., р. 55. 21 Ibid., pp. 1-27.

Meantime the microscope had come into use. In 1619 Harvey discovered the circulation of the blood though he did not publish the fact until 1628. In 1661 Malpighi actually saw the blood circulating through the capillaries. Vesalius (1514-1564) founded a School of Anatomy at Padua.

The attempt to catalog plants and animals was begun by John Ray in the seventeenth century, but the new era in natural science really opened with Linnæus, the Swedish botanist (1707-1778). He held that the creator had produced a pair of each species of animal and that there had been no increase in the number of species. Each species retained its original characteristics. His studies compelled him to modify this attitude. By 1762 he admits the formation of new types and explains this as the result of the crossing of species. "All the species of one genus constituted at first one species; they were subsequently modified by hybrid generation; that is, by intercrossing with other species." 22 In the last edition of his "Systema Nature" (1766) he no longer asserts the fixity of species. He seems to have thought that external conditions could cause degeneration. He based his classification on external characters, while later students depend more upon structure, but this was inevitable, and Linnæus rendered tremendous service by his painstaking observations. It is to him that we are indebted for our system of naming the different species.

22 OSBORN, H. F. о. с., р. 129.

Conservative as Linnæus was, his ideas did not pass unchallenged. His discovery that an alleged miracle water turned into blood - was caused by the appearance of vast multitudes of minute insects, led to his denunciation. One bishop said: "The reddening of water is not natural'... 'when God allows such a miracle to take place Satan endeavors, and so do his ungodly self-reliant, self-sufficient and worldly tools, to make it signify nothing." The discovery is denounced as a "Satanic abyss." 23

As we have seen, Linnæus had been compelled to change his opinion on the fixity of species. Evidence was gathering from several sides on this point. As observations of the same species in different regions increased and specimens were brought together in collections, certain well defined varieties appeared which were not sharply separated at all points but gradually blended. Species considered distinct were found to have intermediate forms. The confidence of the naturalists in the fixity of species was further weakened by the collection of geological specimens. These not merely indicated that many old forms no longer existed, but showed so clearly that present forms bore such close resemblance to the older that the inference that the latter were descended from the former was unavoidable. A third series of significance was that offered by existing life from the simplest organisms through all the forms to man himself. The suggestion that this showed some connection was inevitable. Further evidence was gained from the life history of the individuals of the 23 WHITE, A. D. о. с., p. 61.

higher species which were seen to bear striking resemblance to the existing chain of life from the lowest to the highest forms. There came also a revival of interest in the theories of the Greeks which led the philosophers who were by no means ignorant of the significance of the newer scientific discoveries into a new field of speculation. The last factor was the growth of anatomical knowledge which raised many questions as to the assumed perfection of organisms and indicated that many parts were useless survivals. Thus the way was cleared for a new viewpoint.

The first observer to sense the new order was Buffon (1707-1788). In early life he shared, as did Linnæus, the common viewpoint. Later he changed his views markedly. "The pig does not appear to have been formed upon an original, special and perfect plan, since it is a compound of other animals; it has evidently useless parts, or rather parts of which it cannot make any use, toes all the bones of which are perfectly formed, and which, nevertheless, are of no service to it. Nature is far from subjecting herself to final causes in the formation of her creatures." 24

In middle life he emphasized the rapid variation of species. "One is surprised at the rapidity with which species vary, and the facility with which they lose their primitive characteristics in assuming new forms." 25 Or again: "How many species being perfected or degenerated by the great changes in land and sea, by the favors or disfavors of nature, by food, by the prolonged influences of climate, contrary or favorable, are no longer what they formerly were." 25

Buffon saw the changes caused by domestication of animals. He noted the high birth rate, the struggle for

24 OSBORN, H. F. о. с., р. 132. 25 Ibid, p. 133.

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existence and the elimination of many individuals. He hints at the common ancestry of ass and horse, of man and ape. He thought the environment modified animals and urged that present changes be studied that older changes might be understood. It is hard to judge Buffon. He is frequently contradictory. He recants his opinions when attacked on theological grounds by the Sorbonne. When expressing himself on some moot points he suggests that inasmuch as the Bible teaches the contrary this view cannot be true. He had less influence than Linnæus largely because he was ahead of his time - but he greatly stimulated research.

Erasmus Darwin (1731-1802) squarely broke away from the idea of special creation. He thought that life originated in water:

"Hence without parents, by spontaneous birth,
Rise the first specks of animated earth."

In unmistakable language he pictures the evolution of life from its simplest forms to man himself. "When we revolve in our minds the metamorphosis of animals, as from the tadpole to the frog; secondly, the changes produced by artificial cultivation, as in the breeds of horses, dogs and sheep; thirdly, the changes produced by conditions of climate and of season, as in the sheep of warm climates being covered with hair instead of wool, and the hares and partridges of northern climates becoming white in winter; when, further, we observe the changes of structure produced by habit, as seen especially by men of different occupations; or the changes produced by artificial mutilation and prenatal influences, as in the crossing of species and production of monsters; fourth, when we observe the essential unity of plan in all warm-blooded

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