338 Kansas Academy of Science, 



of this primitive tritubercular ancestral form. Indeed, there 

 is not a part of a vertebrate's body, capable of fossilization, 

 that does not show progressive specialization or reduction. 

 Furthermore, the embryos of mammals, including man, in 

 their development from the fertilized egg, repeat the stages of 

 development of the embryos of their ancestors, from the pro- 

 tozoan ancestor to the present. 



■ Progressive loss of parts is likewise shown in the skeletons 

 of fossil vertebrates. The early Tertiary ancestor of the 

 horse, Eohippus, had four toes on the front foot, and three toes 

 on the hind foot with a rudiment of a fourth toe. Later the 

 ancestor of the horse had but three good toes on each foot ; now 

 the horse has but one toe on each foot, with rudiments under 

 the skin of the second and fourth toes. In all cases the modifi- 

 cations are inherited. The embryo of the modern horse has 

 five toes, but four of them fail to develop. 



The vitalist explains this progressive gain or loss of parts 

 and functions by instancing the well-known fact of observa- 

 tion that every unusual response must be made consciously; 

 after much repetition the act becomes habitual, and in time it 

 is established as instinctive, and is then inherited. But it must 

 be remembered that additional responses in the same direc- 

 tion keep the part growing or diminishing. 



As the inherited parts and powers are ready to function 

 very nearly in the order of their acquisition by the race, the 

 educator needs to be a student of geology, embryology and 

 biology as well as of pedagogy. Professor James says that 

 most people do not realize half of their possibilities, because 

 they do not exercise all their powers of high value even to a 

 safe limit. This dictum has in it certainly a large measure of 

 truth, but is it not also true that people would come more 

 nearly to realizing their true worth if the schools had found 

 appropriate exercise for their powers of value as they arise? 

 Not only should the subjects studied in schools develop in- 

 herited tendencies of high value, but other tendencies of little 

 or no worth should be allowed to become vestigial through the 

 dropping of those school subjects which cultivate them. These 

 latter may well include the purely formal studies of the cur- 



