SCIENTIFIC SUMMARY. 549 
Notices of papers on subjects of interest to microscopists will be found 
under the following heads : — 
Botanical Section — 
Raphides as Characters of Plants. 
Cryptogams in Eggs. 
Chinese Diatom acese. 
Geological Section — 
Exogenous Wood in arenaceous Limestone. 
Minute Geologic Evidence. 
Medical Section — 
Structure of Nerve Cells in the Frog. 
The Development of Fibrine. 
Epilepsy accompanied by Diabetes. 
Nature of Skin Parasites. 
Fatty Degeneration of the Blood. 
Micro-photographs. 
Zoological Section — 
Tubularia not Parthenogenous. 
British Polyzoa. 
Zoosperms in the Ovary of the Snail (?) 
Sphaerularia Bombi. 
MINERALOGY. 
Characters of Tephroite. — The characters of this mineral have hitherto 
been but questionably known, for no effort has been made to distinguish the 
substance from its congeners. Professor G. J. Brush, of Yale College, 
U.S., has therefore done good service in publishing the results of his 
observations. According to this mineralogist, the optical and crystallo- 
graphic characters of tephroite are now clear enough, being similar to 
those of chrysolite ; this isomorphism being further sustained by the 
chemical composition of the two minerals. Before the blowpipe tephroite 
fuses easily to a black mass, fusibility equal 3-5 on Yon Kobell’s scale. 
With the fluxes it gives reaction for silica, manganese, and iron. On char- 
coal, most specimens give traces of zinc due to the mechanical mixture 
with zincite. Heated in the closed tube it gives traces of moisture. 
Hydrochloric acid dissolves it, without an evolution of chlorine, and on 
heating the solution a perfect jelly is formed. It is composed of silica, 
oxides of iron, zinc, and manganese, with small proportions of lime and 
magnesia. Its analyses show that it is to be regarded as a mangancsian 
chrysolite. — Silliman's American Journal , vol. xxxvii. p. 68. 
A new Zeolitic Mineral has been found by Professor How in the trap 
rocks of Nova Scotia, and has been designated Mordenite by its discoverer. 
It occurs in rather small masses, in the form of somewhat cylindrical, 
reniform, or flattened geodes and solid concretions, rather smooth exter- 
nally, sometimes covered with a thin yellowish crust, blotched with a 
green mineral (probably a silicate of iron), and at others, exposing its 
own yellowish white or pinkish-coloured surface. Its interior frequently 
presents hardly any trace of crystallization, but on close examination a 
