70 BIOLOGY AND ITS MAKERS 



Ruysch. In 1664 he discovered the valves of lymphatic 

 vessels by the use of slender glass tubes, and, three years 

 later, first used a waxy material for injecting blood-vessels. 



It should be noted, in passing, that Swammerdam was the 

 first to observe and describe the blood corpuscles. As early 

 as 1658 he described them in the blood of the frog, but not 

 till fifty-seven years after his death were his observations 

 published by Boerhaave, and, therefore, he does not get the 

 credit of this discoverv. Publication alone, not first observa- 

 tion, establishes priority, but there is conclusive evidence 

 that he observed the blood corpuscles before either Malpighi 

 or Leeuwenhoek had published his findings. 



Love of Minute Anatomy. — After graduating in medi- 

 cine he did not practice, but followed his strong inclination 

 to devote himself to minute anatomy. This led to differences 

 with his father, who insisted on his going into practice, but 

 the self-willed stubbornness and firmness of the son now 

 showed themselves. It was to gratify no love of ease that 

 Swammerdam thus held out against his father, but to be 

 able to follow an irresistible leading toward minute anatomy. 

 At last his father planned to stop supplies, in order to force 

 him into the desired channel, but Swammerdam made efforts, 

 without success, to sell his own personal collection and pre- 

 serve his independence. His father died, leaving him suffi- 

 cient property to live on, and brought the controversy to a 

 close soon after the son had consented to yield to his wishes. 



Boerhaave, his fellow-countryman, gathered Swammer- 

 dam's complete writings after his death and published them 

 in 1737 under the title Biblia Naturce. With them is in- 

 cluded a life of Swammerdam, in which a graphic account is 

 given of his phenomenal industry, his intense application, his 

 methods and instruments. Most of the following passages 

 are selected from that work. 



Intensity as a Worker. — He was a very intemperate 



