USE OF THE CAMERA. LOL 
costing only twenty-one marks ($5.25). Most students at first 
find it difficult to use a camera, but practice soon overcomes 
the difficulty and enables one to adjust the illumination prop- 
erly, which otherwise is the principal cause of poor success. 
The other accessories for the microscope which are of 
value to the biologist are a stage micrometer, one or more 
animalcule cages, glass cells, a compressorium (the one des- 
cribed by Mr. Ryder? possesses many advantages and is on 
the whole the best), and a bull’s eye condenser which is neces- 
sary with opaque objects, and when using the higher powers. 
The polariscope is of use in mineralogy and in differentiating 
some animal tissues. Rotary stages, unless accurately cen- 
tred, are useless and then are of value only to the mineral- 
ogists. ‘The stage forceps which accompany most stands are 
models of clumsiness, are wholly worthless, and can well be 
dispensed with. 
In writing the foregoing pages on the microscope and its 
accessories, the writer has had this object in view: to show 
that the simpler an instrument is, other things being equal, 
the better it is, and that none need be deterred from purchas- 
ing a microscope on the grounds that a good instrument 
costs an outrageous amount. Just as soon as American stu- 
dents realize that the simpler their apparatus is the better 
their work will be, just so soon will American science rise 
from its present low level. 
There are three men in America, who never did a single 
stroke of original work in their lives, to whom we are in- 
. 
4 American Naturalist, xiv, p. 691. 1880. 
