134 JOHN SWAMMERDAM. 



scribing the structure of large objects than in de- 

 lineating the organs of the most minute. 



His classification of insects differs very materially 

 from those now in use. The characters of his four 

 classes he derives from the state in which each insect 

 apj3ears after its birth, and those through which it 

 passes before attaining its entire development. In 

 the first he places all those which issue from the egg 

 with nearly the same form as that which they have at 

 the period of their full growth; such as spiders, 

 slugs, leeches, &c. In the second are included 

 those which, like the grashopper, issue with six feet, 

 and some time after cast off the covering under 

 which the wings were concealed. These insects run 

 or leap with agility in their first stage, which is not 

 the case with those of the next class. To the third 

 are referred insects which undergo greater changes, 

 such as caterpillars, and which proceed from the egg 

 in the state of a worm, remain in that state for 

 some time, cast off their hairy covering, assume the 

 form of a chrysalis, when they become motionless, 

 and finally emerge in a winged state. The fourth 

 class consists of such as, like the common fly, on 

 changing the form under which they issued from 

 the egg to assume that of a worm, do not cast 

 their covering, but become separated from it, while 

 it remains and forms a shell or egg-like investiture, 

 in which the insect remains in the pupa state un- 

 til it finally emerges with wings. 



The history of Swammerdam must excite our 

 sympathy and commiseration ; but that, as some 

 liave alleged, he lost his reason towards the end of 

 his life, and became subject to mania, arising from 

 religious melancholy, no one who has any share of 



