Bailey.] "■" [>ray 1, 



most violent controversy. Those persons who conceive these differences 

 to have come into existence full-formed, as they exist at the present time, 

 are those who believe in the dogma of special creations, and they usually 

 add to the doctrine a belief in design in nature. This doctrine of special 

 creation receives its strongest support when persons contrast individual 

 objects in nature. Certainly nothing can seem more unlike in very fun- 

 damental character than an insect and an elephant, a star-fish and a potato, 

 a man and an oak tree. The moment one comes to study the genealo- 

 gies of these subjects or groups, however, he comes upon the astonishing 

 fact that the ancestors are more and more alike the farther back they are 

 traced. In other words, there are great series of convergent histories. 

 Every naturalist, therefore, is compelled to admit that differences in na- 

 ture have somehow been augmented in the long processes of time. It is 

 unnecessary, therefore, that he seek the causes of present differences 

 until he shall have determined the causes of the smallest or original 

 differences. It is thus seen that there are two great and coordinate prob- 

 lems in the study of evolution, the causes of initial differences, and the 

 msans by which differences are augmented. These two problems are no 

 doubt very often expressions of the same force or power, for the augmen- 

 tation of a difference comes about by tiie origination of new degrees of 

 difference, that is, by new differences. It is very probable that the origi- 

 nal genesis of the differences is often due to the operation ot the very 

 same physiological processes which gradually enlarge the difference into 

 a gulf of wide separation. 



In approaching this question of the origin of unlikene&ses, the inquirer 

 must first divest himself of the effects of all previous teaching and think- 

 ing. We have reason to assume that all beings came from one original 

 life-plasma, and we must assume that this plasma had the power of per- 

 petuating its physiological. identity. Most persons still further assume 

 that this plasma must have been endowed with the property of reproduc- 

 ing all its characters of form and habit exactly, but such assumption is 

 wholly gratuitous and is born of the age-long habit of thinking that like 

 produces like. We really have no right to assume either that this plasma 

 was or was not constituted with the power of exact reproduction of all 

 its attril)utes, unless the behavior of its ascendants forces us to the one or 

 the other conclusion. Inasmuch as no two individual organisms ever are 

 or ever have been exactly alike, so far as we can determine, it seems to me 

 to be the logical necessity to assume that like never did and never can 

 produce like. The closer we are able to approach to plasmodial and un- 

 specialized forms of life in our studies of organisms, the more are we im- 

 pressed with the weakness ot the hereditary power. Every tyro in the 

 study of protoplasm knows that the amoeba has no form. The shapes 

 which it assumes are individual, and do not pass to the descendants. To 

 my mind, therefore, it is a more violent assumption to supjiose that this 

 first uuspecialized plasma should exactly reproduce all its minor features 

 than to suppose that it had no distinct hereditary power and therefore, by 



