1901] MICROSCOPICAL JOURNAL. ‘ 15 
to Linnaeus in the latter half of the last century, show how 
vast have been our additions to the knowledge of plants. 
The amount of work for microscopists especially in the latter 
sections, appears to be unlimited. | 
PRESERVATION OF Mrepus#.—Meduse should be killed by 
adding a few drops of concentrated chromic acid to sea-water 
containing them. Then well wash in sea-water until the 
chromic acid has disappeared. 
Gradually add glycerin and alcohol to water, tinitil objects 
are in pure glycerin and alcohol of same specific gravity as 
sea-water. 
FResHwAtEeR EnromostracHa.—Mr. D. J. Scourfield, in 
the Proceedings of the South London Entomological and 
Natural History Society, calls attention to the value of Ento- 
mostracha in experimental biology. “Their commonness in 
all parts of the country, their transparency, the ease with 
which they can be isolated and reared under all sorts of 
conditions, mark out the Entomostracha as particularly well 
fitted for observation in connection with even the most fun- 
damental biological problems of the day.” He adds: “We 
badly want detailed studies on local] faunas, on the seasonal 
distribution and variation of different species, on the faunas 
of various types of ponds, on the food of the most abundant 
forms, and many similar subjects.” 
Causks oF Fracture oF STEEL Rarrs.—The value of the 
microscopical examination of steel will be brought promi- 
nently before the general public by the recently issued re- 
port of the Board of Trade committee appointed to examine 
‘into the cause of fracture of a steel rail at St. Neot’s station 
on Dec. 10, 1895, by which a serious accident happened to 
the down Scotch express. The report itself, dealing as it 
does with various experimental work undertaken by well- 
known experts; is somewhat inconclusive, but the micro- 
scopic examination by Sir William Roberts-Austen gave re- 
sults of the utmost interest and value. Briefly stated, it may 
