PROGRESS IN ANATOMY AND PHYSIOLOGY 



was called an aplanatic combination of lenses, in which, 

 as the name implies, the spherical aberration was largely 

 done away with. It was thought that the use of this 

 Herschel aplanatic combination as an eye - piece, com- 

 bined with the Wollaston doublet for the objective, came 

 as near perfection as the compound microscope was like- 

 ly soon to come. But in reality the instrument thus 

 constructed, though doubtless superior to any predeces- 

 sor, was so defective that for practical purposes the sim- 

 ple- microscope, such as the doublet or the Coddington, 

 was preferable to the more complicated one. 



Many opticians, indeed, quite despaired of ever being 

 able to make a satisfactory refracting compound micro- 

 scope, and some of them had taken up anew Sir Isaac 

 Newton's suggestion in reference to a reflecting micro- 

 scope. In particular, Professor Giovanni Battista Amici, 

 a very famous mathematician and practical optician of 

 Modena, succeeded in constructing a reflecting micro- 

 scope which was said to be superior to any compound 

 microscope of the time, though the events of the ensu- 

 ing years were destined to rob it of all but historical 

 value. For there were others, fortunately, who did not 

 despair of the possibilities of the refracting microscope, 

 and their efforts were destined before long to be crowned 

 with a degree of success not even dreamed of by any 

 preceding generation. 



The man to whom chief credit is due for directing 

 those final steps that made the compound microscope a 

 practical implement instead of a scientific toy was the 

 English amateur optician Joseph Jackson Lister. Com- 

 bining mathematical knowledge with mechanical ingenu- 

 ity, and having the practical aid of the celebrated opti- 

 cian Tulley, he devised formulas for the combination 



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