212 ' BIOLOGY: GENERAL AND MEDICAL 



merit scant attention. He took up the subject from the 

 experimental side and brought it to the point from which 

 no departure has since been possible, namely, that "the 

 egg is the common beginning of all animals" (Ovum esse 

 primordium commune omnibus animalibus). The dis- 

 covery of the spermatozoon was made in 1677 by Ham- 

 men. He showed these little bodies* to Leeuwenhoek, 

 who studied them with enthusiasm and diverted further 

 attention from being bestowed upon the egg by declaring 

 the spermatozoa to be the essential germs and that in 

 them were present the beginnings of the future soul. It 

 was even believed that they were minute living animals 

 of both sexes, capable of coition, etc., and the philosopher 

 Leibnitz declared them immortal. Scientists and philos- 

 ophers soon became divided into two schools, the Ovists 

 and the Ammalculists. As the ideas of the Animal- 

 culists departed so far from the truth as to find no place in 

 modern thought, they can be dismissed with the remark 

 that, following Plantade (1699), they eventually came to 

 see in the human spermatozoon a complete miniature 

 of the human fcetus, enclosed in its membranes, its 

 head bowed upon its breast, and its limbs flexed the 

 "homonculus" and supposed that when such an entity 

 was properly received by the uterus it proceeded to grow 

 into a human being. 



The Ovists, on the other hand, regarded the sperma- 

 tozoon with comparative indifference. Some believed 

 it to be a parasitic animalcule of the semen, others con- 

 ceived that it carried some stimulating force by which 

 the growth of the egg was stimulated. They all agreed 

 that it was in the ovum that the future being was con- 

 tained. The ideas of the philosophically minded of this 

 school eventually crystallized into the " preformation 

 theory," or "theory of evolution," by which it was sup- 

 posed that the ovum of every animal contained a minia- 

 ture of the future adult, complete in every detail, and 

 only requiring nourishment in order that it should 

 grow larger and larger until the adult size was reached. 

 "There is no such thing as becoming," is the way it is 



