38 THE AMERICAN MONTHLY (February, 
appeared to be thoroughly permeated by the paraffine. After washing off the superflu- 
ous stain in alcohol 94%, picked up the section with the forceps, and put on a clean 
cover-glass, one or two drops of benzole dissolved the paraffine and cleared the section, 
then. a drop of balsam on the slide, drazuing off the benzole from the cover and plac- 
ing the cover on the drop of balsam, as early parallel with the slide as possible, to avoid 
displacing the object, the operation was finished. I cut, stained, and mounted eighteen 
slides between 8 and 10 P. M._ The benzole appears to be quite sticky when partially 
evaporated, at all events enough so to hold the tissue in place on the cover, if the cover 
is zo¢ tipped up as advised in every microscopical work I ever read. I believe it is the 
cause of more lost sections and hard words than any other operation of mounting. 
The sections may be double stained, and will stand considerable handling. The tur- 
pentine hardens the tissue to a slight degree, and the warm paraffine much more so— 
enough to cut good sections when imbedded according to Dr. Reeves’ method, which 
is the best I ever tried. If the tissue is placed in alcohol long enough to coagulate the 
albuminous portion, it is, I think, all that is necessary. A prolonged immersion in 
alcohol interferes with a proper soaking in the melted paraffine, causing the brittleness 
complained of. 
I send you one of the sections cut last Saturday simply as a sample of the cutting ; 
the staining could be much improved on, 
Dr. Reeves’ section flattener is ‘immense.’ Hard and soft paraffine as recommended 
by you I have never had a good result from. With a hollow-ground knife the cutting 
edge resembles a chisel, and the thicker part acts as a guide, throwing up the section 
and curling it. Jay L. SMItE 
89 Beekman street, New York City. 
MICROSCOPICAL SOCIETIES. 
WASHINGTON MICROSCOPICAL SOCIETY. 
At the 53d regular meeting of the Washington Microscopical Society, Dr. E. M. 
Scheeffer gave an account of what was being done in the way of establishing a sub- 
section on microscopy at the coming meeting of the International Medical Congress, 
which will occur in Washington in September next. The subject will be under the 
nominal charge of the Section on Pathology, but under the immediate charge of Dr. 
Scheeffer. It is desired to make the exhibit as large and attractive as possible and to 
vary it during each day of thé Congress. Circulars will soon be ready giving full 
information, and particulars may be obtained by addressing Dr. Scheeffer, at 1319 F 
street N.W., Washington, D. C. 
O 
At the 54th regular meeting, January 25, the essay of the evening was by Dr. E. P. 
Howland, who gave his experience in microscopic projection, illustrating his remarks 
by an instrument combining a projecting microscope and a lantern for projection of 
photographs. He said :—My experience leads me to believe that the direct projection 
of microscopic objects can only be successfully accomplished in small rooms. For 
public exhibitions and for projection generally, photographs are to be preferred, The 
use of a projecting microscope is quite satisfactory with low powers, but it is difficult 
to concentrate the light sufficiently to admit of the use of high powers. These remarks 
refer to the use of calcium light. With the electric light better results may be obtained. 
I have succeeded in making the electric light perfectly steady by getting all the forces 
into equilibrium, but the cost of using it is a great drawback. I have not succeeded 
in finding any dynamo which will furnish a steady light, and have been compelled to 
use the battery as a source of electricity. Where the object is so delicate as to be 
injured by the heat of the calcium light, the alum cell may be interposed. 
The essay was fully illustrated. Mounted objects on ordinary slides were projected, 
and also photographs of the same objects, showing clearly that the photographs were 
more satisfactory for projection; living animalcule and physical experiments were 
also projected. One of the most striking illustrations was a double projection. By the 
microscope was projected a small electro-magnet, weighing only one grain, wound with 
a few inches of No. 4o silk-covered copper wire, while by the lantern was shown the 
small battery which generated the current. Upon making the necessary connections, 
they were shown side by side on the screen, the magnet attracting small pieces of iron 
wire, and the battery at work, with bubbles of hydrogen ascending as the decomposi- 
tion of the water went on. The objects were erected by use of an obtuse-angled 
