1887.] MICROSCOPICAL JOURNAL. 215 
from fat from the inguinal or abdominal region of a mammal, and, having 
spread it out, to stain with a concentrated solution of ‘fuchsin diluted with 
an equal volume of water, and then stain under the cover-glass where the 
preparation lies in half per cent. solution. For permanent preparations 
picro-carmine, glycerin.—J. R. M. S. 
O 
How to draw with the camera lucida.—In order to draw a picture by 
means of the camera lucida without painfully straining the eyes, it is neces- 
sary that the microscopic image and the paper and pencil be uniformly illu- 
minated. If the image has, in comparison with the paper, too strong a light, 
the pencil will be seen with difficulty, if at all. On the contrary, if the paper, 
in comparison to the image, be too strongly illuminated, the delicate outlines 
of the latter will be indistinct. This difficulty may be remedied by throwing 
either the image or the paper into a shadow. Both may be done simply with 
the hand, or by a properly constructed screen of paper, or by a disk of paste- 
board set up at some distance, and the like. A few trials with the microscope 
with different magnifications will afford the necessary experience for properly 
managing the light. In tracing the outlines of the image under the camera 
the pencil used should not be too hard, and the lines should be very light. 
, ——o 
Double staining botanical preparations.—The following method is 
suggested by Prof. J. J. Rothrock, ofthe University of Pennsylvania :—Immerse 
the section in an extremely weak solution of anilin green for twenty-four 
hours. At the end of twelve hours the section will most likely have absorbed 
all the green, in which case add two drops more of the mother solution. 
Then take a middling strong solution of Beale’s carmine, and immerse the 
section in it for from one to five minutes only ; then prepare with alcohol and 
oil of cloves in the usual way, bedding in dammar lac or Canada balsam.— 
Eng. Mechanic, Sept. 2,’87. 
—O 8 
Mounting perishable crystal sections.—A mounting medium should 
be transparent, and colorless if possible, of an index of refraction having ref- 
erence to the subject treated, and free from moisture. It must not be a solvent 
of the matters that it is employed to preserve. As media of this kind espe- 
cially worthy of attention for mounting perishable crystals, or such as lose 
their polish or become opaque in Canada balsam, as well as in the air, Prof. 
Johnstone, of Johns Hopkins University, recommends the following :—(1) 
Finest gum copal dissolved in chemically pure absolute alcohol; (2) Finest 
copal dissolved in chemically pure absolute alcohol; (3) dammar resin 
dissolved in rectified spirit of turpentine. No heat should be used in 
making these solutions, and the resultant liquid should be very thick. (4) 
Dammar resin dissolved in well-boiled balsam copaiba ; (5) boiled Chian tur- 
pentine dissolved in boiled balsam copaiba; (6) dammar resin boiled until 
the rising scum becomes nearly dissipated, the remaining scum to be removed 
with a spoon. 
EDITORIAL. 
The death of Professor Spenser Fullerton Baird has doubtless long 
since become known to our readers. Professor Baird has been since 1850 
intimately connected with the best scientific work in this country, especially 
in the department of zoology, and has created the U. S. Fish Commission and 
the National Museum. Of the importance of the former institution we 
