ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
491 
prepared by soaking ordinary cotton in a solution of water 100, alcohol 20, 
copper sulphate 3. The cotton should be dried slowly, as it chars easily. 
By this method tubes can be kept unchanged for at least three 
months, i.e. there is no evaporation and no contamination. 
Fixative Solutions.* — Dr. K. Tellyesniczky discusses the value of 
a large number of fixative fluids, and gives a very long list of these 
solutions and the original references thereto. The solutions are con- 
sidered in order of ascending complexity, simple solutions of one 
reagent being first treated of. The double, triple, and quadruple solu- 
tions arc subdivided into those which do and those which do not contain 
acetic acid. In fact, the author’s paper is in praise of the neglected 
virtues of acetic acid. This acid, used in connection with plasma- 
preserving reage’hts such as potassium bichromate and osmic acid, gives 
extremely satisfactory results. 
There are numerous formulas containing bichromate, osmic acid, and 
acetic acid, and other fixatives such as sublimate, picric acid, and nitric 
acid. These are too well known, under the names of their inventors, such 
as Perenyi, Flemming, Altmann, Eabl, Zenker, to need further description. 
To a mixture of 3 grm. potassium bichromate, 5ccm. acetic acid, and 
water 100 ccm., the author’s own name is attached. Small pieces of 
material are left in this fluid for one or two days, and larger ones for 
longer. After removal they are thoroughly washed in water, and then 
further hardened in alcohol of increasing strength, beginning at 15 per cent. 
Method for the Preservation of Protoplasmic Spinnings.f — Mr. G. 
F. Andrews gives the following as being the best method for the preser- 
vation of protoplasmic processes. The fumes of 2 per cent, osmic acid 
are concentrated by heat in a glass chamber. For this was used a large 
closed tube whose base rested on each side on a glass slide, leaving just 
space enough in the centre for a third slide to be slipped in and out. 
The whole stood on a glass plate on a water-bath. The central slide 
carried a watch-glass of osmic acid solution whose ingress and egress 
was provided for by a hole in the glass tube, which can be closed by a 
rubber band. When the fumes were sufficiently concentrated, the central 
slide was replaced by another of like size. On this the eggs had been 
previously arranged with just enough water to cover them. After 
fixation and removal from the chamber, the eggs were washed in many 
changes of water. The exact length of time the eggs should be ex- 
posed to the fumes cannot be given ; but in any case it is very short, a 
second too much or too little either way spoiling the result. The best 
preservative was found to be concentrated sea-water. 
Method for Fixing Leucocytes and Blood-plates.J— Dr. H. Deeljen 
recommends that the blood draw n from the finger should be received on 
a film of agar, to which 0*75 per cent, of NaCl has been added. On 
this the cover-glass is placed. When examined on the warm stage the 
white corpuscles are seen to be in an actively motile condition. The 
preparations were next fixed with formalin or osmic acid vapour, and 
afterwards may be stained in the usual way. 
* Arch. Mikr. Anat. u. Entwickl., lii. (1898) pp. 202-47 (1 pi. and 38 figs.). 
t Zeitsckr. f. wiss. Mikr., xiv. (1898) pp. 447-52. 
X Munchen. Med. Wochenschr., 1897, pp. 1192-3. 
1898 2 l 
