ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
539 
and it is so disposed that the abdomen lies in the cell. The lymph 
flows into the cell, and after adding to it some 0*7 per cent, salt solution, 
the viscera are placed therein, and the intestine, having been spread 
round the edge of the hole, is fastened down with needles. By this 
means the Malpighian vessels can be observed in the living condition. 
To iodine-green they behave during life in a manner quite different 
from that after death. In the first case the nucleus does not stain at 
all, while the protoplasm assumes a purple- violet hue. After death the 
nuclei, which have then acquired an acid reaction, stain green, and the 
protoplasm bluish-green. Another differential stain is the Ehrlich- 
Biondi solution, which colours the nuclei green and the protoplasm 
orange. The other stains mentioned imparted a diffuse coloration or 
were otherwise imperfect. 
Preparing and Staining the Ova of Chironomus.* — Herr B. Bitter 
obtains the ova of Chironomus from the water in which they have been 
laid daring the twilight. The secretion which holds the eggs together 
swells up into a gelatinous mass. The egg-mass is then killed with 
hot 30 per cent, alcohol to which some sublimate has been added, and 
afterwards treated successively with 70, 90, and 100 per cent, spirit. 
It is then imbedded in paraffin after having been soaked in chloroform. 
The author succeeded in staining the ova (a very difficult task) by 
placing the whole egg-mass for at least four days in picrocarmine, the 
transference from the absolute alcohol to the staining fluid being made 
very gradually. The sections may be contrast stained with hiematoxylin. 
Preserving Xarvse of Lepidoptera with their Colour.f — Sig. F. 
Crosa places the caterpillars in a 5 per cent, solution of chloride of zinc, 
and then heats the fluid almost to boiling. This hastens the process 
and prevents putrefaction. The objects are then placed successively in 
10, 15, 20 per cent, solutions of the same salt, and remain therein until 
they sink to the bottom. For a caterpillar of medium size eight to ten 
days are necessary. After the last solution they are placed in glycerin. 
The zinc chloride must be perfectly neutral and contain no trace of iron 
salts. For this purpose commercial zinc is dissolved in pure hydro- 
chloric acid, taking care that the zinc is always in excess, in order to 
prevent the formation of iron chloride ; afterwards it is filtered. If 
commercial zinc chloride be employed, this is dissolved in water acidu- 
lated with hydrochloric acid and then boiled for some time with zinc. 
It is advisable that before the treatment is commenced the caterpillars 
should be made to fast, and that they should be killed with chloroform. 
It is stated that, prepared by this method, caterpillars retain their colours 
(even the green and yellow hues ) for quite two years, and that they are 
quite suitable for histological purposes. 
Method of observing Pectinatella gelatinosa-t — Mr. A. Oka states 
that this Polyzoon is remarkable for the ease with which it can be killed 
in an expanded condition. When 70 per cent, alcohol is gradually 
* Zeitschr. f. Wiss. Zool., 1. (1890) pp. 408-27 (1 pi.). See Zeitschr. f. Wiss. 
Mikr., viii. (1891) pp. 87-8. 
f Boll. Mus. Zool. ed Anat. Comp. Torino, v. (1890) No. 85. See Zeitschr. f. 
Wiss. Mikr., viii. (1891) p. 86. 
t Journ. Coll, of Science, Imper. Univ. Japan, iv. (1891) pp. 91-2. 
2 p 2 
