28 Microscopes at the American Exhibition. By J. G. Hunt. 
I see cause to fear that micro-photography may, for a time, 
retard the best construction of lenses for histological work ; espe- 
cially that oblique micro-photography, whose best results are often 
only diffraction spectra, which leave it doubtful whether the lens 
or illumination was the chief factor in obtaining the result. Pho- 
tography, at its best, gives only approximate representations of 
delicate structural details ; and it is not yet proven that objectives 
so afflicted with strabismus are best for biological work. 
Our best modern high-angle lenses have in them optical capa- 
cities not adequately developed by our present defective plans of 
illumination. Universal absence of absolute central light marks 
most microscopes, and accurate means of obtaining it, modified or 
concentrated at will, is a greater need at the present time, than 
further improvement in lenses. If we observe critically, all mi- 
nutest details, as shown under most microscopes, are fringed with 
diffraction phenomena which can be removed often by simply im- 
proving the light. Even for coarser microscopical work attention 
to the light is universally neglected. Most instruments have no 
adequate provision whatever for accuracy of observation, hence mis- 
interpretation is so common under the higher powers. The Ame- 
rican microscopist has lenses, in common use, which will easily 
define Bacteria if our means of illumination shall be improved. 
The results of microscopical work have interested our members 
on many occasions. Processes of demonstration, of comparatively 
recent origin, have given preparations of higher character than 
were attainable before. Our market is still too liberally supplied 
with foreign refuse material of this kind. Best work, in this de- 
partment, is always kept at home. We import that which is un- 
saleable abroad. To this statement there are a few exceptions. In 
animal histology no one now hopes to see any foreign work worth 
having. In pathology, always more difficult of demonstration than 
normal tissues, we expect neither appreciation nor help from be- 
yond the sea ; yet it is not from talking members of pathological 
societies that we obtain best work. The Army Medical Museum, 
at Washington, has produced the finest pathological work, that is, 
work retaining most structural details, if not most neatly mounted 
that 1 have seen from other sources. In our Centennial there was 
nothing respectable from abroad in this department. Some of this 
imported stuff from Germany is abominable. 
In demonstrating and mounting botanical subjects, this country 
is immeasurably in advance of all others. Some workers here offer 
preparations which are models of technological skill and of surpass- 
ing neatness. Every cell is revealed without dissection, and dif- 
ferentiated by double staining in most beautiful manner. But in 
this kind of work all structural details are not preserved. The 
cells are empty. None but the botanist will ever do best botanical 
