SCIENTIFIC RESEARCH 247 



azines, when an antitoxin for diphtheria or a method of 

 preventing typhoid fever has been announced. But these 

 are only the recent pages of a book long in the making, to 

 find the title page of which we must turn back through 

 many years and to matters having little apparent connection 

 with what is now before us. 



To illustrate this last statement, let us trace the course of 

 man's discoveries regarding the microorganisms, taking as a 

 convenient starting point the year (1676) when the Hol- 

 lander, Anthony van Leeuwenhoek, discovered with the 

 microscope, but lately come into use as a toy and source of 

 amusement, what he described as "little animals observed 

 in rain, well, sea, and snow water as also in water wherein 

 pepper had lain infused." 3 Leeuwenhoek's discoveries were 

 no doubt regarded as useless by his contemporaries, save a 

 few by whom his work was highly esteemed. The possession 

 of a modest income enabled him to devote a generous portion 

 of his time to study; and at the end of a long life he had 

 examined with his microscope all he could lay hands upon in 

 both animate and inanimate nature. Among other things, 

 he discovered some of the larger bacteria, many protozoa, 

 the passage of blood from arteries to veins through the 

 capillaries (the one link needed to complete Harvey's evi- 

 dence for circulation) ; and he was the first to describe, if not 

 the discoverer of, the human spermatozoon. 4 

 He became the first great microscopist. Thus at first: 



"We were dreamers, dreaming greatly, 

 in the man-stifled town; 

 We yearned beyond the sky-line where 

 the strange roads go down." 



3 See: Kent, W. Sayville, "Manual of the Infusoria," for quotations from, 

 and an account of, the work of Leeuwenhoek. 



4 Interesting facts regarding the life and work of Leeuwenhoek will be found 

 in the article by D. F. Harris, "Anthony van Leeuwenhoek the First Bac- 

 teriologist," Scientific Monthly, Feb., 1921. Cf. also: Locy, ''Biology and its 

 Makers." 



