APPENDIX. 291 



Swammerdam *, and Lyonnet f were made by instruments 

 such as these. The numerous difficulties which attended 

 the fabrication of such small lenses, induced several ob- 

 servers to endeavour to find some substitute for them. 

 In this manner successive trials were made with pure 

 water, sulphuric acid, and castor oil, which were used 



* Swammerdam Avas born at Amsterdam in 1637, and died in 

 1680, from the effects of a hypochondriacal affection aggravated 

 by excessive devotion to study. In one of his fits of melancholy he 

 threw a great part of his manuscript into the fire, imagining that it 

 was an offence against God to attempt to unravel the anatomical 

 structure of insects ! On another occasion he sold for a paltry sum 

 a mass of his manuscripts, which were recovered at a great cost by 

 Boerhaave, and published under the title of Biblia Naturce. Swam- 

 merdam appears to have been one of the first who practised the art 

 of anatomical injections ; but his chief celebrity rests upon his 

 anatomical researches on Insects, 



f Lyonnet, -who was born at Maestricht, and died at the Hague 

 in 1789, devoted himself for a time to the study of the bar, and 

 even pleaded several important causes. By way of relaxation he 

 employed himself in studying the natural sciences, and more 

 especially the history of Insects. He had originally intended to 

 publish a general -work on the subject, but having been annoyed to 

 find that several of his discoveries had already been published by 

 other naturalists, he resolved to undertake a work in which he 

 would not have to fear competition from any one. With this 

 object in view, he undertook to study the anatomy of an Insect 

 more thoroughly in detail than human anatomy had ever been 

 studied, and he chose a species of Phalena or Moth, whose larva 

 gnaws the bark of willow trees, elms, &c. (Cossus ligidperda). 

 Lyonnet had proposed to himself to study successively the larva or 

 caterpillar, the nympha or chrysalis, and the perfect insect ; but 

 in consequence of his public duties he was unable for several years 

 to do more than complete the first part of his work. This treatise, 

 which was entitled le Traite anatomique de la Chenille du Sauk, 

 appeared in 1762, in a large quarto volume, accompanied by eighteen 

 plates, which had been engraved by the author himself. " This 

 work," says Cuvier, " is the chef-d'oeuvre of anatomy and engrav- 

 ing " — a eulogy which it merits even at the present day. 



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