706 SUMMARY OF CURRENT RESEARCHES RELATING TO 
Formol or Formaldehyde.* * * § — Mr. A. B, Lee points out that the 
already extensive literature which treats of the uses of formaldehyde is 
much confused by the inaccurate use of the terms formol, formalin, and 
formaldehyde. The last is the chemical name of the compound HCOH. 
Formol is the commercial name given by Schering & Co. to a 40 per 
cent, solution of this substance in water. Formalin is the commercial 
name given to the same solution by Meister, Lucius and Briining. The 
proper way of stating the strength of solutions is to say formol or 
formalin diluted with so many volumes of water. 
Preservation of Cladocera.f — Herr T. Stingelin, after trying various 
methods for preserving Cladocera, found that it was best to content 
himself with the exclusive use of a 4 per cent, watery solution of cor- 
rosive sublimate. Specimens were at once washed in 65 per cent, 
alcohol, stained in alum-alcohol for at most three minutes, placed in a 
12 per cent, solution of alum, and then washed in water. Hardening 
was effected in the ordinary ascending grades of concentration of alcohol. 
The author is well satisfied with the preparations which he got. 
Catching and Preserving Medusae. :J — Mr. E. T. Browne states that 
his latest method for catching Medusae is to use a long tow-net made of 
bolting silk with a mesh not exceeding • 05 mm. At the end of the net 
is fastened a zinc can, instead of the usual glass bottle which generally 
breaks when the contents are specially wanted. The author prefers to 
use a small rowing-boat and work very gently against the tide, with just 
a slight pull on the net. If the Medusae are not visible ac the surface, 
the net should be sunk about two fathoms, and, if not successful, it 
should be tried near the bottom. It is well to remember that Medusae 
are very delicate, and quickly die if they are crowded together in a 
small bottle. The following is given as one of the best methods for 
killing and preserving small specimens. Place the Medusa in a large 
watch-glass with sufficient water to float in. Add with a pipette about 
5 drops of a 2 per cent, solution of cocain, and about 10 minutes later 
add another 5 to 10 drops. When the Medusa has become motionless 
and the tentacles expanded, add suddenly a saturated solution of picric 
acid. It is best to reduce with a pipette the quantity of water in the 
watch-glass just before adding the picric acid, and to use plenty of 
the latter. Often when the picric acid is added a precipitate of cocain 
is thrown down, which must be removed at once by a pipette, and fresh 
picric acid added. After being in the acid about half an hour specimens 
should be gradually transferred to 80 per cent, alcohol. The author 
strongly recommends the use of the best glass-stoppered bottles and 
perfectly pure .spirit for storing specimens in. 
(6) Miscellaneous. 
Method for Counting Blood-corpuscles.§ — Herr P. Domeny suggests 
the following method for counting blood-corpuscles or other bodies 
suspended in a fluid, such as bacteria, algae, infusoria, &c. A slight 
* Anat. Anzeig., xi. (1895) pp. 255 and 6. 
t Rev. Suisse Zool., iii. (1895) p. 165. 
X Proc. and Trans. Liverpool Biol. Soc., ix. (1895) pp. 245 and 6. 
§ Zeitschr. f. Angewaudte Mikroskopie, i. (1895) pp. 168-71. 
