380 General Biology 



was sure he saw definitely-formed tiny human beings in the spermatozoa. 

 A great conflict was waged by those who agreed with him and his 

 school, who were known as spermists, insisting that it was the sperm 

 that was the all important factor in producing life, and the opposing 

 school known as ovists which insisted that it was the egg and not the 

 spermatozoa which developed into new offspring. 



Swammerdam (1637-1680), in his Biblia Naturae, compiled long and 

 painstaking accounts of his researches on the anatomy of insects. Up 

 to his time, insects were considered only unorganized physical masses. 



Malpighi (1628-1694) of Bologna worked on plants and animals. 

 He made elaborate studies and illustrated them, on the development of 

 the plant-embryo, as well as on the embryology of the chick, the 

 anatomy of the silk-worm, and the structure of glands. 



Chronologically, the systematists should be mentioned at this point, 

 but logically, it is better to introduce the student to the whole subject 

 of classification and the men who did the classifying at the same time. 

 Therefore, this subject will be treated in the next chapter. 



As soon as there is any considerable classification and description 

 of a subject, men begin to divide that subject into individual parts or 

 units so that workers may narrow their field and confine their work to 

 such a limited group or unit. 



Comparative anatomy, physiology, histology, embryology, genetics, 

 and organic evolution, are the main divisions into which Biology is thus 

 divided. 



The work done by first-year students of Biology, as set forth in 

 this book, consists of studying a type-form of the principal phyla of 

 plants and animals, and then attempting to develop biological principles 

 from the knowledge thus gained. This first-year work, therefore, in- 

 cludes the fundamentals of botany and zoology. The third semester's 

 work is confined to the specialized study of embryology, and the fourth 

 semester's work is comparative anatomy and physiology. In this last 

 semester's work the student studies in detail each organ or organ-system 

 of the great divisions of zoology and then compares these, system by 

 system. 



Probably the first man to attempt this latter method was Severinus 

 (1580-1656) of Naples. In 1645 he published a volume suggesting that 

 all vertebrates and man had much in common, structurally. However, 

 over a century before this time, Belon had made drawings of the skel- 

 etons of birds and man and placed them side by side so that differences 

 and similarities could be noted. Then came Tyson (1650-1708) of Cam- 

 bridge, who is the father of our modern method of treating comparative 

 findings in monograph form. His work was a comparison of man and 

 monkeys. 



Cuvier (1769-1832) of Paris is, however, the first of the great men 

 in this field of work. He was the first to embrace both living and extinct 



