THE MIcRoscoPE. 53 
clamped at any desired point upon the sliding framework, inde- 
_ pendently of the rear part which carries the focusing screen ; 
an indispensable feature in securing the exact enlargement or 
reduction that may be necessary. The front of the camera is 
fitted with a double shifting arrangement, (vertical and hori- 
zontal,) for exact centering of the negative, which is firmly 
held in position by spring clips, and is provided with kits 
whereby quarter or half plates may be used as desired. The 
practical use of this apparatus in making lantern transparencies 
will be fully explained in a later article. | 
The camera and its component parts having now been de- 
scribed, and presuming my readers are provided with a micro- 
scope of some kind, it will be my pleasant duty in the next 
_paper to unite these two important factors in the production of 
a photo-micrograph, and to explain clearly as possible how the 
latter may be made by any one willing to exercise a little care 
and patience. Comparatively few and inexpensive appliances 
and materials, other than those heretofore named are needed. 
Sensitized plates of course, a non actinic lantern, for placing 
same in the holder, and for development, a few flat dishes and 
chemicals, which will be duly named, include all the requisites 
for the work. It is merely a matter of simple chemistry, of 
brains and of patience; and the results are worth all the pains- 
taking required and more too. 
STRAY NOTES ON SOME FRESH-WATER INFUSORIA. 
D. S. KELLICOTT. 
() looking over some notes made during the past summer I 
find several references to encysted forms and developmen- 
tal phenomena. Some of these present features differing in so 
interesting a manner from recorded examples that I have 
thought an account of them worth the space it will occupy in 
Tue Microscope and submit the following for the judgment of 
others. 
The encystment of minute animals, for example, Rotifera 
and Infusoria, is an act which, when understood and its results 
considered, is truly wonderful. For a long time we were told 
by authority, and few disputed it, that rotifers could be desic- 
