ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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into tlie fluid. They are tlien observed either in a capillary space 
formed by a combination of cover-glasses, or in the culture-apparatus for 
running water described by the author. The chromoplasts have the 
appearance of being compressed by an outer elastic layer. The isolated 
protoplasts were found to be surrounded by a clear margin which is in 
active motion, and is composed of cilium-like threads. The inner 
side of the wall of the vacuoles was in places clothed by streams of 
granular protoplasm. The observations were made chiefly on Stratiotes 
aloides. 
Histological Observations on Hydromedusse.*— Dr. M. Chapeaux, 
in using the teasing method, fixed the polyps with a mixture of * 1 per 
cent, osmic acid and *2 per cent, acetic acid, in which they were left for 
some time ; they were then placed for twenty-four hours in 1 per cent, 
acetic acid. Maceration being finished, the tissues were teased, and 
various carmines or haematoxylin were used for staining ; this was 
effected with difficulty. If maceration was effected with 1 per cent, osmic 
acid for from twelve to twenty-four hours, it was impossible to stain the 
elements, but teasing was easy, and the cells did not really require to 
be stained. 
If it is proposed to make sections, the best method for fixing the 
polyps in a state of extension is to treat them with 1 per cent, osmic 
acid for fifteen hours, or 2 per cent, for a less time ; the protoplasm of 
the cells is stained yellowish brown, while the contained granulations 
are of a dark hue. Flemming’s solution may be used, and although 
concentrated sublimate does not give equally good results, tissues that 
have been treated with it can be stained. 
Graafian Follicle.f — Dr. J. Schottlaender in his study of Graafian 
follicles used Flemming’s chromo-osmic-acetic mixture, Rabl’s platinum 
chloride and ckromo-formic acid method, &c. Safranin, gentian-violet, 
alizarin, &c., were used as stains ; celloidin and photoxylin for imbed- 
ding. 
Methods of Decalcification, t — Prof. S. H. Gage discusses the 
methods of decalcification in which the structural elements are preserved. 
He points out the necessity of a “ restrainer ” or chemical substance, 
which will restrain the decalcifier from injuring the soft parts. In 1888 
it was discovered that the gelatinizing and softening action of nitric 
acid — the great decalcifier — was almost wholly obviated by the use of a 
saturated aqueous solution of alum to every 100 ccm. of which 2 grm. 
of chloral hydrate are added. As a satisfactory fixer and hardener, the 
author recommends a mixture of 500 ccm. water, 500 ccm. 95 per cent, 
alcohol, and 2 grm. of picric acid. The tissue is left one to three days 
in the picric alcohol, one to three days in 67 per cent, alcohol, and then 
put in 82 per cent, alcohol. For decalcification 67 per cent, alcohol 
and 3 ccm. strong nitric acid may be used, when the alcohol acts on the 
restrainer; or use is made of a saturated aqueous solution of alum 
diluted with an equal volume of water, to every 100 ccm. of which 5 ccm. 
* Arch. de Biol., xii. (1892) pp. 661 and 665. 
f Arch. f. Mikr. Anat., xli. (1893) pp. 219-91 (2 pis.). 
X Proc. Amer. Micr. Soc., xiv. (1893) pp. 121-4. 
