14 



The office of one of these arms was to hold the little corpuscle, 

 and that of the other to apply the niicrosct)pe. His 

 microscopes were of various sizes and curvatures, his 

 microscopical glasses being of various diameters and focuses, 

 and, from the least to the greatest, the best that could be 

 procured, in regard to the exactness of the workmanship and 

 the transparency of the substance. He was so incomparably 

 dexterous in the management of these useful instruments 

 that he made every observation subservient to the next, and 

 all tend to confirm each other, and complete the description. 

 But the constructing of very fine scissors, and giving them 

 an extreme sharpness, seems to have been his chief secret. 

 These he made use of to cut minute objects, because they 

 dissected them equably, whereas knives and lancers are apt to 

 disorder delicate substances. His knives, lancets, and styles 

 were so very fine that he could not see to sharpen them 

 without the assistance of the microsco^De : but with them he 

 could dissect the intestines of bees with the same accuracy and 

 distinctness that others do those of large animals." 



There is little doubt Swammcrdam mounted microscopic 

 slides. Bnerhaave says: — "He discovered that the fat nf all 

 insects was perfectly dissolvable in oil of turpentine, and 

 that they could not be preserved in balsam, and this discovery 

 he always made the greatest secret of, because the fat of 

 insects, when melted and then dried, looks like lime scattered 

 over the parts, so as to obscure the viscera, and make it 

 impossible to examine them. Thus he Ijegan, carried forward, 

 and perfected without any assistance, in a private and 

 middling station of life, more discoveries than all the writers 

 of all the preceding ages." The book is profusely illustrated 

 with beautiful copper-plate engravings. 



Shortly aftei-, i'l 1758, Moses Harris published "77/^ 

 .lure} id n or Xatiiral Jlisfor;/ of J'Jvtflinh Inserts, namely, 

 Butte rjiies and MofIi!<, 'Tot/e'her with the Plants on whirh 

 the// feed. A faithful aeroun' of their respectire chanr/es .■ 

 their usual Haunts, when in tJie winr/ed state : and their 

 Standard names as r/iven and established In/ the worthy and 

 ingenious Sorieti/ of Aurelians." The name of Moses Harris 



