22 MEMOIR OF SWAMMERDAM. 



There Le continued for two years, labouring with 

 such diligence and success, that he not only secured 

 the high approbation of his instructors, but on 

 the llth October 1663, was admitted to the rank 

 of a candidate of physic. At this time the study of 

 human anatomy seems chiefly to have engaged his 

 attention, and he made various trials to accomplish 

 an object which has frequently been attempted since, 

 namely, to preserve anatomical dissections in such a 

 way that they might serve for demonstrations, and 

 supersede the necessity of employing so many sub- 

 jects. His zeal for anatomy led him to cultivate the 

 friendship of every one eminent in that department, 

 and they, in their turn, were not slow in appreciating 

 his genius and enthusiasm. He formed a lasting 

 friendship with Nicholas Steno, and was likewise 

 intimate, for a time, with Rynier de Graaf, two of 

 the most distinguished anatomists of that age. 



About this time he appears to have first engaged 

 in experiments on the respiratory system of frogs, a 

 subject to which he often reverted, and which he 

 illustrated with great diligence and success. 



In 1664, he made a journey into France, and re- 

 sided for some time in the house of Tanaquil Faber, 

 at Saumur. While there, his attention was much 

 occupied with the examination of the internal struc- 

 ture of insects, in which he made several discoveries. 

 Of these, the most important was the valves of what 

 Boerhaave calls the lymphatic vessels, which he detec- 

 ted by means of very slender tubes, which he had now 

 acquired the art of employing, with great effect, for the 



