ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
579 
iodine, two parts iodide of potassium, and a hundred parts water ; dry 
with blotting-paper, and further decolorise in a mixture of anilin oil 
two parts with xylol one part. When sections are sufficiently de- 
colorised, they should be washed two or three times and mounted in 
xylol-balsam. 
The Marchi method is recommended for discovering whether or no 
a process of degeneration is going on in the nerve-cell. 
Preservation of Marine Animals.* — Mr. E. T. Browne remarks 
that the introduction of formaldehyde as a preserving fluid, instead of 
alcohol, is of great importance to the marine naturalist, especially when 
working in localities where it is difficult to obtain a supply of good 
spirit. He first tried formaldehyde for preserving marine animals at 
Yalentia last year. The results, both for hydroids and medusae, were 
far superior to those obtained by means of alcohol. The colouring, 
however, is not permanently preserved. The best results with hydroids 
and medusae have been obtained when the specimen has been killed by 
a fixing reagent, and then placed first into a 2 * 5 per cent, solution and 
finally into a 5 per cent, solution. 
Object-Holder for the Observation of Objects enclosed between 
Two Cover-Glasses.f — Dr. C. J. Cori uses an object-holder, such as is 
represented in fig. 93, when it is necessary to examine small objects 
mounted between two cover-glasses on both sides. It consists of an 
Fig. 93. 
oblong brass plate, 9 cm. long and 4 cm. broad, with a rectangular 
aperture of dimensions 30 by 35 mm. This aperture can be diminished 
at will by a sliding panel which serves to firmly clamp the cover-glasses 
containing the objects to be examiued, which are supported in grooves 
on the sides of the aperture. 
Preserving Yeast in Saccharose Solution. :J — Herr J. C. Holm men- 
tions two modifications of Hansen’s flasks which are used in Jdrgensen’s 
laboratory for keeping yeasts. In these flasks the culture remains 
unimpaired for many months, and the medium does not deteriorate from 
evaporation or contamination. From the verbal description, a bent tube 
connected with the cup of the flask is the essential part of the apparatus. 
No illustration is given. 
* Proc. Zool. Soc. Lond., 1896, pp. 460 and 1. 
t Zeitschr. f. wiss. Mikr., xii. (1896) pp. 300-1. 
X Centralbl. f. Bakteriol. u. Parasiteuk., 2 te Abt., ii. (1896) pp. 313-6. 
