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PROGRESS OF MICROSCOPICAL SCIENCE. 
are attached spine-like epithelial cells ; the scale of a flattened shaft, 
so to speak, covered by analogous structures. I may state that the 
scales or even hairs from the live insect are not in a fit condition to 
break ; they are too pliable and tough, so that I have not succeeded 
in doing anything in the way of breaking when the scales were in this 
state. By carefully drying in an ordinary drying oven, such as is 
used in chemical laboratories for drying precipitates, &c., the scales 
become much more brittle, and the greasy substance that can be 
pressed from them while fresh entirely disappears through the agency 
of a gentle and continued heating. It will require a discharge of 
some force to break off the spines, and several discharges in rapid 
succession will give best results. As it is desirable to examine the 
scales immediately after the action of the spark, some arrangement 
similar to that used in Germany for acting upon tissues with the 
induced current is most convenient. A rather thick glass slide, with 
two pieces of tin-foil pasted upon it at a distance apart just sufficient 
to allow of the passage of the spark, with the scales in the pathway 
of the discharge covered by another slide or strong cover glass, will 
make a simple and effective instrument. It must not be supposed that 
the blowing off of the spines is to be accomplished at every attempt. 
I find that when the spark passes across the scale from side to side, so 
as to strike the spines on their lateral surfaces, the chances are best 
of rending off the spines. Many attempts must fail, and many a fine 
“ Test Podura” will have to be sacrificed, as the scales, either un- 
touched or in fragments, will be oftentimes scattered to such an extent 
that only here and there on the slide can one be found ; and then to 
mount the individual on a clean slide with thin cover, in order to 
examine with higher powers, is a very difficult matter. 
The Anatomy of Balantidium coli . — The ‘Northern Archives of 
Medicine ’ contains a paper by M. P. J. Wising, of Stockholm, on the 
anatomy and physiology of Balantidium coli, a parasite first described 
by Professor Malmsten in 1856. In 1869 a labourer, Lars Nilsson, 
sixty-two years of age, noticed for the first time the presence of small 
white worms in the motions from his bowels. About Christmas of 
that year he suddenly became affected with severe colicky pains, fol- 
lowed by considerable diarrhoea. This at last became so bad that there 
were as many as twelve stools a day ; they were usually of the con- 
sistence of thin pea-soup, sometimes with firmer lumps intermixed, 
sometimes quite watery, and most frequently tolerably small in 
quantity. There was but slight tenesmus, while after some time the 
stools were streaked with blood. The microscope showed, in addition 
to the remains of food, a good many lymphoid cells, a few red blood- 
corpuscles, vibriones, and Balantidium coli in very large numbers. 
The more original researches of the author are directed to the 
question of the reproduction and propagation of the parasite. In a 
series of beautifully-executed lithographs the anatomical structure of 
the animal, including the peristome, with its adoral cilife, nucleus, 
nucleolus, and contractile vacuoles, the phenomena of coition and the 
process of reproduction, are represented. The last-named is carried 
on in this way. The body of the parasite elongates so that its length 
