376 MICROSCOPY. 
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necessary. Colors may be added, if desired, by a sable-hair pencil. 
The surface is then protected, and ‘the drawing instantly changed 
- into a transparency, by flowing thin balsam over it and allowing 
it to dry as a thin film over the surface. In the same manner 
illustrations of subjects not microscopical may be easily and 
rapidly prepared. 
Popura ScaLes.—A happy accident has furnished Mr. F. H. 
Wenham a supply of specimens that seem to confirm the theory 
he so strongly defends of the reality of the spines on this most 
disputed of “tests.” A favorite specimen which contained a 
detached spine having been destroyed, and an effort to remove 
uninjured the large scales which adhered to the broken cover-glass 
having failed, he scraped off the scales at random with a sharp 
knife edge and mounted the fragments, and was pleased to find 
many of the fragments cut obliquely in such manner as to leave 
the spines (!) cut at a different plane and manifestly projecting 
yond the other portions. Mr. Wenham’s drawings certainly 
seem to confirm his descriptions, and photographs of the same 
appearances are promised. 
Lenetuenep Immersion Tusr.— Mr. E. Richards, of the Royal 
Microscopical Society, renders the familiar immersion arrange- 
ment available in deep water, eight to ten inches, by screwing in 
an adapter between the objective and the nose piece of the micro- 
scope. This carries the objective with its immersion cap down 
through the stage and into a tank of water beneath it. 
Automatic TURN-TABLE.— Dr. F. B. Kimball prefers this 
arrangement to the usual method of turning by hand. He uses 
the works of a common clock, putting a pin through the shaft x 
the table and cutting a slot in the hand arbor of the clock-work, 
and then mounting the turn-table so that the pin will catch in the 
slot and the two move together. 
_ OriciN or BLoop Corruscres.—Dr. H. D. Schmidt, of New 
Orleans, has communicated an elaborate study of this subject to 
the Royal Microscopical Society. His studies were chiefly directed 
to human embryos of six weeks old, and upward. He is eon 
vinced that the nucleus only, of the colorless blood-corpuscles, 1 
developed into the red corpuscle. He strongly confirms the prev- 
alent opinion that the spleen and lymphatic glands are the perme 
