ON MICROSCOPICAL DRAWING AND PAINTING. 175 



if selenite films be dispensed with, some results may, 

 with care, be recorded ; petrological preparations, 

 the dichroism of crystals, sections of shell, bone, 

 scales, horn, and other semi-transparent organic 

 structures of varying densities, reveal points of 

 interest only seen under such conditions and may 

 be noted ; but considering that the most exalted 

 light at the command of the artist, is the white 

 of the paper (in all cases, to be jealously preserved), 

 and that the polariscope discloses the purest coloured 

 lights, associated with complementary tones of every 

 gradation, it is clear how futile are the resources of 

 the palette to depict the lustres and unisons of 

 tones as revealed by this fascinating instrument. 



Structure and its thoughtful exposition is the 

 limit of draughtsmanship, and it is here that the 

 photographic lens as a delineator fails; the superiority 

 of work produced by a hand guided by cultivated 

 observation as compared with a photograph is the 

 operation of a mind capable of expressing combined 

 and superimposed tissues, in having at command a 

 control and adjustment of various planes of surfaces, 

 and without militating against scientific truth, seek- 

 ing for, and obtaining even picturesque effects, 

 this important power is felt when searching the 

 depths of an opaque injection, or peering into 

 intricacies of tissues. Tbe objective used in micro- 

 photography, especially if it be a high power (un- 

 like the penetrating quality of an ordinary portrait 

 lens), is strictly limited to one, and that a very 

 delicate focal plane requiring a fine and FINAL 

 adjustment, enhanced by the difficulty that the 

 visual and chemical foci of microscopic objectives 

 do not coincide, entailing a manipulation which 



