Tue Microscope. 267 
specimen more attractive to the naked eye and that too without 
expenditure of extra time. 
3. PreRMANENT Caustic Potash PREPARATIONS. It is usually 
stated that specimens treated with caustic potash cannot be per- 
manently preserved. During the past summer an aqueous solu- 
tion of caustic potash of thirty-five to forty per cent. was used for 
isolating cardiac muscle from many different animals; as some of 
the preparations were drawn it seemed unfortunate not to be able 
to render them permanent as vouchers for the drawings. This was 
accomplished by adding glacial acetic acid to the isolated cells. 
The acid combines with the caustic potash to form acetate of pot- 
ash, which is often used for permanent mounting; finally a mix- 
ture of glycerin seventy-five parts and an aqueous solution of 
picro-carmine (one per cent.) was added as a permanent mounting 
medium. These specimens after three months show no signs of 
deterioration. If the specimens were already under the cover- 
glass, a drop of glacial acetic acid was drawn under it and after- 
ward a drop of the glycerin and picrocarmine mixture. 
4, PAPER FOR CLEANING THE LENSES OF OBJECTIVES AND 
Ocutars. For the last two years the so-called Japanese filter paper 
(the bibulous paper often used by dentists when filling teeth) has 
been used in the laboratory for cleaning the lenses of oculars and 
objectives, and especially for removing the fluid used with immer- 
sion objectives. Whenever a piece is used once it is thrown away. 
It has proved more satisfactory than cloth or chamois, because 
dust and sand are not present; and from its bibulous character it 
is very efficient in removing liquid or semi-liquid substances. 
At the writer’s suggestion it was tried in the Bureau of Animal 
Industry at Washington, and is now used there almost exclusively 
for the purpose named above. 
5. DEMONSTRATION OF THE FIBRILLAE OF UNSTRIATED Mus- 
CULAR Fiprers. For demonstrating the longitudinal fibrillation of 
unstriated muscular fibers the following method has proved very 
satisfactory: Ten to fifteen cm. of perfectly fresh small intestine 
from a cat or other animal is tied at one end and into the other is 
injected (with the injecting jar, see fig. 1.) the following mixture: 
ninety-five per cent. alcohol, twenty-five cc., water seventy-five cc. 
picric acid crystals three-fourths of a gram. When the intestine is 
