682 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
improvement, was applied to embryo lungs for the purpose of demonstrat- 
ing the shape of the air-passages and saccules. The preparations are 
immersed for a short time in a mixture of two parts chloroform and one 
part oil of cloves. They arc then removed, and dried on filter-paper. 
When the preparation begins to turn white (less than 5 minutes), it is 
transferred to oil of cloves. The spaces in the labyrinth are now filled 
with air or a mixture of air and chloroform vapour, and when examined 
by reflected light look as if they were filled with quicksilver. Though the 
picture may last long enough to take a drawing or a photograph, it is a 
transient one, owing to the absorption of the air by the oil of cloves. 
More lasting preparations were obtained from embryo lungs. In this 
case a solution of finely powdered Indian ink was used. The solution 
was sucked in through the trachea as the air disappeared from the lung, 
and in this way beautiful preparations of the shape of the air-passages 
and air-sacs were obtained. 
The photographs given of lung preparations of the embryos of rabbits 
and fowl are excellent demonstration objects. 
Removal of Pigment from Zoological Specimens.* — Dr. R. Jander 
recommends Fol’s decalcifying solution for removing pigment from 
zoological specimens, such as mantle of Lamellibranchs, leeches, Arthro- 
pods’ eyes, fish-skins, &c. 
The solution consists of one per cent, chromic acid, 70 vols. ; nitric 
acid, 3 vols.; water, 200 vols. 
The pigment is removed in from 12 to 48 hours, according to the 
bulk of the object. The solution may be used for sections as well as 
for whole objects. Sections must be stuck on by means of some adhesive, 
such as very thin albumen. 
The solution has the further advantage of fixing and decolorising 
simultaneously. The acids are easily removed by means of water. 
Hardening Blood, Sputum, &c., on Slides. j — Dr. C. Ritter prefers 
slides to cover-glasses for making preparations of morbid and other 
fluids, such as blood, pus, sputum, urine. The fluid should be poured on, 
and the slides placed in glass capsules or vessels containing the fixative, 
such as osmic acid or formalin. The slides are made to rest on fillets 
or blocks with the film side downwards, so as to expose the surface to 
the action of the reagent. 
Demonstrating Medullated Nerve-fibres.;]; — Herr A. E. Smirnow 
demonstrates the medullated nerve-fibres in the molecular layer of the 
cerebellum by the Weigert-Pal and Golgi methods. The whole cere- 
bellum of a freshly killed dog is placed in a mixture of 4 parts of 5 per 
cent, bichromate of potash and 1 part of formol for 1-8 weeks. The 
organ is then cut in half and immersed in 3-5 per cent, bichromate of 
potash solution, which is renewed daily for a week. After an immersion 
of from 2-5 weeks, one-half is treated by the Weigert-Pal method, and 
the other cut up into pieces of 1-2 cm. in length. 
These pieces are placed in the following mixture : — Five per cent, 
bichi ornate of potash, 5 vols.; 2 per cent, osmic acid, 1 vol. After 
* Zeitschr. f. wiss. Mikr., xv. (1898) pp. 163-5. 
t Tom. cit., pp. 159-61 (2 figs.). 
X Arch. f. Mikr. Anat., lii. (1898) pp. 195-202 (1 pi.). See Zeitschr. f. wiss. 
Mikr., xv. (1898) pp. 246-7. 
