THE STORY OF NINETEENTH-CENTURY SCIENCE 



of lenses of crown glass with others of flint glass, so 

 adjusted that the refractive errors of one were corrected 

 or compensated by the other, with the result of produc- 

 ing lenses of hitherto unequalled powers of definition; 

 lenses capable of showing an image highly magnified, 

 yet relatively free from those distortions and fringes of 

 color that had heretofore been so disastrous to true in- 

 terpretation of magnified structures. 



Lister had begun his studies of the lens in 1821, 

 but i-t was not until 1830 that he contributed to the 

 Royal Society the famous paper detailing his theories 

 and experiments. Soon after this various Continental 

 opticians who had long been working along similar lines 

 took the matter up, and their expositions, in particular 

 that of Amici, introduced the improved compound mi- 

 croscope to the attention of microscopists everywhere. 

 And it required but the most casual trial to convince 

 the experienced observers that a new implement of sci- 

 entific research had. been placed in their hands which 

 carried them a long step nearer the observation of the 

 intimate physical processes which lie at the foundation 

 of vital phenomena. For the physiologist, this perfec- 

 tion of the compound microscope had the same signifi- 

 cance that the discovery of America had for the fifteenth- 

 century geographers it promised a veritable world of 

 utterly novel revelations. Nor was the fulfilment of 

 that promise long delayed. 



in 



Indeed, so numerous and so important were the dis- 

 coveries now made in the realm of minute anatomy that 

 the rise of histology to the rank of an independent sci- 



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