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PROGRESS OF MICROSCOPICAL SCIENCE. 
Cryptogamic Botany at Harvard University , U.S.A. — On the 6th 
of last month (July) a course of practical instruction on cryptogamic 
botany was begun in this locality, and we think the idea deserves 
to be carried out in some of our own universities and schools. The 
following is the plan of operations : — Microscopes and all necessary 
equipments are provided by the university, but students are expected 
to bring sharp razors, razor strops, dissecting needles, slides, and 
covering glasses. No provision, however, is made for drying and 
preparing specimens other than microscopic. A knowledge of the 
rudiments of phasnogamic botany is required of those taking this 
course, or in case of those wishing to pursue the subject in connection 
with zoological studies, a practical acquaintance with the working of 
the compound microscope. A general course of lectures will be given 
upon the structure and development of Thallogens, and on one day of 
the week an excursion will be made either into the country or to the 
sea-shore. Laboratory instruction will be given every day except 
Saturday, and the method of examining Fungi and Algte and the 
manner of making microscopic preparations will be taught. Illustra- 
tions of the structure, and, as far as time will allow, of the develop- 
ment of the principal orders of Fungi and Algae will be afforded each 
student, and an opportunity will be given to become familiar with the 
more common moulds, blights, and with a few agarics. Students who 
have attended a previous course can pursue more in detail any branch 
of the subject they may prefer. Under certain restrictions, students 
may consult the extensive cryptogamic collections and library of the 
University. 
The Structure of the Genus Siphonia. — Mr. W. J. Sollas read a 
paper on the above subject before the Geological Society on May 23. 
This paper contained, first, a full account of the history of the genus 
Siphonia, including a complete list of its described species, and, next, 
a description of its general and minute structure. Its skeletal net- 
work was shown to consist of spicular elements belonging to the 
Lithistid type of sponges, and most closely allied in generic details to 
the recent form Discodermia polydiscus. Not only in this character 
but in every other, Siphonia was shown to approach Discodermia so 
closely as to be almost identical with it. The mineral replacements 
which have affected the siliceous skeleton of Siphonia were then 
considered. The paper concluded with a systematic description of 
the genus. 
The Nervous Arrangements in the Ovary. — We learn from the 
‘ Medical Record ’ that Herr J. Elischer has recently investigated 
the ovaries of the cow, sheep, and rabbit. The organs were hardened 
for a short time in a 2 per cent, solution of ammonium bichromate, 
the fluid being changed daily, and then coloured with chloride of gold 
and sodium after the manner of Gerlach and Boll. In all cases, fine 
medullated nerve-fibres were found to pass into the stroma on the 
vessels. From the middle of the hilus they branched in two ways. 
