MODERN MICROSCOPY 



INTRODUCTION. 



To attempt to give a historical account of the development 

 of the microscope, tracing it through its pre-achromatic 

 days, and noting the successive improvements that have 

 contributed to the high position it occupies to-day amongst 

 instruments of precision, would alone fill a small volume. 

 Suffice it to say that so recently as the year 1824 Tully 

 constructed his first Achromatic Microscope, since which 

 time every decade has added its tale to the march of 

 progress. In 1883 the President of the American Society 

 of Microscopists, in his annual address, remarked ' that 

 lenses, which were believed to have so nearly reached the 

 limit of perfection fifteen years ago, are antiquated now, 

 and the limit of perfection has moved forward like the 

 horizon, and is as far off as ever.' Those who are 

 acquainted with the development of the microscope and 

 its appurtenances since that time are aware that greater 

 progress has been attained in recent years than had ever 

 been made before. With the introduction of the system of 

 lenses, termed the ' apochromatic objectives,' microscopical 

 optics were raised to an entirely new plane, for these lenses 

 were of a nature altogether superior to those of their pre- 

 decessors. Subsequently a new and increased variety of 

 optical glasses from which to manufacture their lenses 

 was placed at the disposal of opticians, and from that time 



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