THE MICROSCOPE IN MODERN PHARMACY 



About the year 1800 the number of forms of simple microscopes 

 was multitudinous. Spherical and chromatic aberrations were in a 

 large measure corrected by employing combinations of lenses, as in 

 modern simple microscopes. Cuff made a simple microscope which 

 was capable of being converted into a compound microscope. 



The First Compound Microscope was made in 1590 by Z. Janssen, 

 a spectacle maker of Middleburg, Holland. The exact construction 

 of this instrument is apparently not known. It is said to have been 

 an imposing affair, consisting of a copper tube, 6 feet long, with three 

 lenses mounted upon brass dolphins. Janssen made several instru- 

 ments, one of which is still preserved at Middleburg and of which 

 Fig. 3 is a diagram. These micro- 

 scopes were of no practical value, be- 

 cause the image was greatly distorted 

 and discolored. They were looked 

 upon as curiosities rather than instru- 

 ments of scientific precision. 



Even as late as 1821 such eminent 

 authorities as M. Biot, of France, and 

 Dr. Wollaston, of England, declared 

 that "the compound microscope will 

 never excel the simple one." 



According to Van Heurck, the 

 oldest compound microscope of which 

 there is any figure is that of R. Hooke 

 (1665). It is evident that the size of 

 the microscopes was greatly reduced FIG. 2. Wilson's simple microscope 

 about this time, the tube in the Hooke (1740). 



instrument being only about 18 centi- a > l ens ; & > gl ass discs f r holding: 

 metres (7 inches) in length; there were, ob J ects ' c > adjustable mirror; d, foot 

 , ,. , i T . , . . , i or base ; e, stand, 



however, four tubes sliding into each 



other capable of being drawn out to increase magnification. The field 

 lens (middle lens) was removable. Illumination was vertical by means 

 of a lamp, spherical and bull's-eye condensers. In spite of its complex 

 mechanism it was far from being a satisfactory instrument. 



Grindelin (1687) made a compound microscope which showed 

 considerable improvement. Chromatic and spherical aberration were 

 in part corrected by the use of combinations of lenses. The field 

 lenses were more generally used. While the arrangement of lenses in 

 this instrument indicates considerable progress, the mechanical parts 

 were defective. There were neither condensers nor adjustable mirror. 

 Cuff's microscope, which was patented in 1714, was provided with a 



