22 
MEMOIR OF SWAMMERDAM. 
There lie continued for two years, labouring with 
such diligence and success, that he not only secured 
the high approbation of his instructors, but on 
the 11th October 1G63, 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 
