86 



BIOLOGY AND ITS MAKERS 



mammals circular. He reserved the term ' globule ' for 

 those of the human body, erroneously believing them to 

 be spheroidal. 



Other Discoveries. — Among his other discoveries bear- 

 ing on physiology and medicine may be mentioned: the 

 branched character of heart muscles, the stripe in voluntary 

 muscles, the structure of the crystalline lens, the description 

 of spermatozoa after they had been pointed out to him in 

 1674 by Hamen, a medical student in Leyden, etc. Richard- 

 son dignified him with the title ' the founder of histology,' 

 but this, in view of the work of his great contemporary, 

 Malpighi, seems to me an overestimate. 



Turning his microscope in all directions, he examined 



water and found it peopled with minute animalcules, those 



simple forms of animal life propelled through the water byj 



innumerable hair-like cilia extending from the body like 



banks of oars from a galley, except that in 



many cases they extend from all surfaces. 



He saw not only the animalcules, but also 



the cilia that move their bodies. 



He also discovered the Rotifers, those 



favorites of the amateur microscopists, made 



so familiar to the general public in works 



like Gosse's Evenings at the Microscope. 



He observed that when water containing 



these animalcules 



evaporated they were 



reduced to fine dust, 



but became alive 



again, after great 



lapses of time, by the 



introduction of water. 



Fig. 2 i.-Plant Cells. (From Leeuwen- He made man >' 



hoek's Arcana Natures.) observations on the 



