436 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of magnesium completely anaesthetizes them ; it is well to use rather 
stronger solutions (about • 4 per cent.) for them. 
Observation of Blood of Astacus.* — Mr. W. B. Hardy obtained the 
blood of the Crayfish by aid of a glass pipette drawn out to a fine point 
and pushed through the soft skin which joins the dorsal portion of the 
cephalothoracic shield to the tergum of the first abdominal appendage. 
The pipette is fitted with a strong india-rubber bag, by the aid of which 
fluid may be sucked up into the tube. The skin is stretched by pushing 
down the abdomen of the Crayfish, and the point of the pipette is inserted 
from the side and horizontally so as to avoid injuring the heart and 
superior abdominal artery. A drop or two of blood being sucked up, 
the abdomen is quickly bent upwards so as to mechanically close the 
tiny aperture. A blood-clot will soon form, and the Crayfish may be 
replaced in the tank without any further loss of blood. 
Permanent preparations may be made by inverting a drop of blood 
over a 2 per cent, solution of osmic acid ; after 15 minutes the blood 
can be stained and mounted in glycerin or balsam. A reagent of the 
very greatest value in the study of the corpuscles is iodine. 
Study of Cutaneous Glands of Crustacea. t — M. M. Ide fixed small 
marine species, such as Vibila or Phronima, by plunging them entire 
into Kleinenberg’s solution, picrosulphuric acid, or 70 per cent, alcohol. 
With larger species, such as Asellus or Oniscus, the head was cut off and 
plunged in water saturated with corrosive sublimate or Gilson’s solution 
(acid sublimate). For the glands of the urostvle of Oniscus, which are 
very difficult to reach, the ends of the urostyles must be cut off, and 
Gilson’s solution injected into the body of the animal till it escapes by 
the cut extremities ; the caudal portion must then be cut off with scissors 
and left for ten minutes in a bath of the fixing solution. Sections should 
be coloured on the slide either with alum picrocarmine alone or by it, 
followed with picric acid or watery blue carmine. 
Study of Compound Eyes of Annelids.J — Mr. E. A. Andrews mace- 
rated the eyes of Annelids in Bela Haller’s liquid, in potassium bichro- 
mate, and in sea-water containing a small amount of sulphuric acid ; the 
last method was found very useful. The staining reagents used were 
Mayer’s acid carmine, Czokor’s cochineal, and methyl-green. Sections 
were stained with Kleinenberg’s hsematoxylin, and Grenacher’s fluid 
was used for depigmentation. 
Examination of Ciliated Organs of Hirudinea.§— Prof. H. Bolsius 
has, in his general study of the segmental organ, chiefly employed the 
method of serial sections ; these, it is to be observed, were not made on 
extirpated organs, but on entire individuals. This is the most advan- 
tageous method, as the organs are too delicate for ordinary dissection. In 
teased preparations the best staining agent was found to be methyl-green. 
Preparation of Echinoderms.||— Mr. G. W. Field recommends the 
following method of preparing large starfishes, such as Oreaster. Kill 
* Journal of Physiology, xiii. (1892) pp. 165-6. 
t La Cellule, vii. (1891) pp. 352-3. 
J Journal of Morphology, v. (1891) pp. 272-7. 
§ La Cellule, vii. (1891) p. 296. 
j| John Hopkins Uuiv. Cire., xi. (1892) p. 84. 
