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Printing the positives is done in the usual manner made 
use of in producing portraits and views. 
I have given the preparations I use and it will be seen 
that they differ in no respects from those used in portrait or 
view work; in fact Photomicrography, as far as the chemi- 
cals and formulze go, is essentially the same as ordinary 
photography, only greater care is required in securing accuracy 
of proportions, and above all things cleanliness is absolutely 
necessary. Iam convinced that if more attention were paid to 
this last injunction by our photographers generally, we 
should have better pictures than they commonly present us. 
With regard to instruments, an ordinary microscope can be 
used if it be merely made to replace the lens tube on a portrait 
camera-box but I use a microscope made on purpose, having 
a flange by means of which it is attached to the front of 
the camera\ Great steadiness is an absolute essential in 
Photomicography and I find that shutters and slides of all 
kinds to be used in exposing are detrimental. I withdraw 
the slide from the plate-holder, after having hung a bent 
card over the object on the opposite side to the objective ; 
then, when everything has come to a state of rest, carefully 
remove this card and expose. If the camera be placed upon 
the earth, not in a building, all the better; and if the opera- 
tions be carried on away from all streets and roads, still 
better. 
If the lenses used be not specially constructed for photo- 
graphy, so as to bring the chemical and visual foci coincident, 
the chemical focus can be found either by practice, by using 
an Ammonio-Copper screen, as described by Dr. Woodward, 
or by employing a glass prism to illuminate the object. Any 
or all of these plans are desirable and easy of application. 
In short, this brief communication has been more for the 
purpose of showing that there really are no great difficulties 
present, in the practice of this extremely beautiful and valua- 
ble method of reproducing representations of objects of 
natural history. Any careful portrait or view manipulator, 
can easily become a good photomicrographist, by merely 
attending to the injunctions as laid down in our simplest and 
