THE nic Tin:!': .wn its sroin' 



17 



Hut naturall>' a widtM- and deeper 

 kiU)wliHl«!;e of l)i()l()<i;i('al phenomena was 

 ne('(\ssary hei'oi'e philosopliieal l)iolo«i\' 

 could liave a stron*;- foundation. Hence 

 the philosophy of zo6ioj2;y in its modern 

 form, dates from the a\vakenin<»; of 

 science in the sovontoenth century. 



From the time that the 1M<>; Tree was 

 a mere seedling up to the time that it 

 measunxl fully 13 feet in diameter, 

 there was scarcely a single discovery in 

 the field of natural science worthy of 

 record. One event, however, which 

 occurred when the tree measured only 

 12 inches in circumference is of some 

 interest. Silk was one of the treasures 

 obtained from the Far East. Its 

 production was carried on solely by 

 the Chinese, who jealousty guarded 

 the silkworms and their eggs. The 

 story is that two monks travelling in 

 China succeeded in smuggling some 

 eggs out of the country by concealing 

 them in a hollow cane, and brought 

 them into Europe. In the warm clim- 

 ate of the south the eggs developed into 

 strong healthy worms. From such a 

 humble beginning arose the extensive 

 silk industry of southern Europe. 



The stagnation of the study of 

 anatomy for more than a thousand 

 years was due to an extravagant admir- 

 ation of Galen, over-confidence in his 

 writings, and the failure of men to 

 make observations for themselves, or 

 to believe what they saw^ with their 

 own eyes. Vesalius (born in 1514) 

 was the first anatomist to assert inde- 

 pendence, and to him is due the credit 

 of laying the foundations of modern 

 anatomy. Vesalius dissected the 

 human body and accurately described 

 what he found. He established a school 

 of anatomy at Padua, and among his 

 students was Fabricius, the teacher of 



ilar\'ey, who >taitle(l the world in HiP.» 

 with his (ii>co\-ery of the cii-ciilat ion of 

 (he blood. This discovery, which 

 r< volutioni/ed the study of j)hysiology, 

 antl gave new iin|)etus to the study of 

 anatomy, met with bitter ()])p()sition 

 from th(* followers of (lalen, but Har- 

 vey defended his views with success. 



The opposition to Harvey set men to 

 thinking, and investigation began. 

 All forms of life were studied with all 

 available means. Harvey, from an 

 investigation of the development of 

 the chick, laid the foundations of the 

 study of comparative embryolog}^ one 

 of the four great supports of the theory 

 of evolution; and he also propounded 

 the theory of Epigenesis, a theory 

 vigorously debated by philosophers for 

 many years. The compound micro- 

 scope, already mentioned, was applied 

 to the study of organisms by Leeu- 

 wenhoek and Malpighi. The former 

 demonstrated capillary circulation 

 (1690) and discovered red blood cor- 

 puscles, infusoria and spermatozoa 

 (1677). These spermatozoa were 

 regarded by some as parasites of animal 

 bodies, b}^ others as embryos which 

 only needed nourishment t:o develop 

 into an adult form. Malpighi applied 

 the microscope to the study of the 

 chick, and his observations led him to 

 announce the theory of Preformation, 

 which was opposed to the epigenesis 

 of Harvey. 



The preformatlonists contended that 

 a given organism contained within its 

 sperm or ovum all the descendants of 

 that individual with all organs and 

 parts fully formed. In other words, 

 embryos were only miniature adults, 

 and were contained one within another 

 like a series of Chinese boxes, in suc- 

 cesive grades of size. The doctrine 



