The Pamphlet Collection of Sir Robert Stout: Volume 29
Evidence of Intermediate forms
Evidence of Intermediate forms.
I now pass on to the consideration of those cases which are not—for the reason which I will point out to you by-and-by—demonstrative of the truth of Evolution, but which are such as must exist if Evolution be true, and which therefore are upon the whole strongly in favor of the doctrine. If the doctrine of Evolution be true, it follows that animals and plants, however diverse they may be—however diverse the different groups of animals, however diverse the different groups of plants—must have all been connected together by gradational forms; so that, from the highest animals, whatever they may be, down to the lowest speck of gelatinous matter in which life can be manifested, there must be a sure and progressive body of evidence—a series of gradations by which you could pass from one end of the series to the other. Undoubtedly that is a necessary postulate of the doctrine of Evolution. But when we look upon animated nature as it at present exists, we find something totally different from this. We find that animals and plants fall into groups, the different members of which are pretty closely allied together, but which are separated by great breaks at intervals from other groups. And I cannot at present find any intermediate forms which bridge over these gaps or intervals. To illustrate what I mean; Let me call your attention to those vertebrate animals which are more familiar to you—such as mammals, and birds, and reptiles. At the present day these groups of animals are perfectly well defined from one another. We know of no animal now living which in any sense is intermediate between the mammal and the bird, or between the bird and reptile. But, on the contrary, there are actually some very distinct and anotomical peculiarities, well defined marks, by which the mammal is separated from the bird, and the bird from the reptile. The distinctions are apparent and striking if you compare together the different divisions of these great groups. At the present day there are numerous forms of what we may call broadly the pig tribe, and many varieties of ruminants. These latter have their definite characteristics, and the former have their distinguishing peculiarities. But there is nothing that comes between these ruminants and the other tribe, the pig tribe. The two are distinct. So also is this page 22 the case between the groups of another class—the reptiles. We have crocodiles, lizards, snakes, turtles, and tortoises, and yet there is nothing—no connecting link—between the crocodile and lizard, or between the lizard and snake, or between the snake and crocodile, or between any two of these groups. They are separated by absolute breaks. If then it could be shown that this state of things was from the beginning—had always existed—it would be fatal to the doctrine of Evolution. If the intermediate gradations which the doctrine of Evolution postulates must have existed between these groups—if they are not to be found anywhere in the records of the past history of the Globe—all that is so much a strong and weighty argument against Evolution. While, on the other hand, if such intermediate forms are to be found, that is so much to the good of Evolution, although for the reason which I will put before you by-and-by, we must be cautious in assuming such facts as proofs of the theory.
It is a very remarkable fact that, from the first commencement of the serious study of palæontology, from the time in fact when Cuvier made his brilliant researches in respect to animals found in the quarries of Montmartre—from that time palæontology has shown what she was going to do in this matter, and what kind of evidence it lay in her power to produce. I said just now that at the present day the group of piglike animals and the group of ruminants are entirely distinct; but one of the first of Cuvier's discoveries was an animal which he called the Anoplotherium, and which he showed to be, in a great many important respects, intermediate in its character between the pigs on the one hand and the ruminants on the other; that in fact research into the history of the past did so far—and to the extent which Cuvier indicated—tend to fill up the breach between the group of ruminants and the group of pigs.