286 
late number of his ‘Archiv’ (vii, p. 180) points out that 
glycerine, in spite of its undoubted merits as a fluid medium 
for preparations of animal tissues, has the great drawbacks of 
causing too great transparency, dissolving fatty molecules, and 
so on, while it is particularly unsuitable for objects which 
have been hardened or preserved in osmic acid. None of 
these disadvantages belong to a nearly concentrated aqueous 
solution of acetate of potash; which may, like glycerine, be 
allowed to run in without removing the cover-glass, and will 
then replace the water or other fluid in which the object is 
immersed. After twenty-four hours, when the water is evapo- 
rated and the saline solution has completely replaced it, the 
cover may be cemented down. As the fluid neither dries up 
nor crystallises, the preparations may, if desired, be left some 
time without any cement. This medium is said to possess all 
the advantages with none of the drawbacks of glycerine. 
The latter has the great disadvantage of turning specimens 
treated with osmic acid dark brown or black, and so destroying 
the preparation if every trace of the acid be not washed out 
before mounting, and this is not possible. Since the very ex- 
tensive use of osmic acid, of which Professor Max Schultze 
recently spoke to us as neither more nor less than ‘ himmlisch,’ 
and of such fascinating power as to make one desire to give 
up everything else and work all day with the microscope, it 
becomes very desirable to have some other preservative fluid 
than glycerine. 
Parasitic Ear Fungi.—‘ The Bulletin de la Société Imperiale 
des Naturalistes de Moscou,’ No. 1 for 1870 (just published), 
contains a paper by Dr. Karsten on the parasitic fungi found 
in the human ear, with copious illustrations. ‘The writer con- 
firms the statements made by Hallier and other previous 
observers, that when the spores of these fungi are sown 
elsewhere, they assume very different forms, according as the 
matrix on which they are sown is rich or poor in material for 
nutrition ; and that fungi described by earlier writers as distinct 
species, or even as belonging to different genera, are 
frequently merely different forms in the genetic cycle of the 
same plant. 
Chemical Society. Fungi in Potable Water. — Professor 
Frankland, F.R.S., read a paper “On the Development of 
Fungi in Potable Water.” He began by alluding to the ex- 
periments Dr. Heisch had made some months back with 
water contaminated with sewage matter. When to such 
waters some sugar was added, very soon a kind of fer- 
mentation ensued, and a rich fungoid growth made its 
appearance. Professor Frankland has now repeated and 
