ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
483 
methyl-alcohol for the production of gaseous formic aldehyde. The 
horizontal chimney is In two parts ; the vaporising portion, which 
contains a Krell’s platinum wire core, being placed on top of the wick- 
tube. The wick-tube is heated until the escaping alcohol vapour ignites, 
and then the platinum core is inserted into the vaporising tube. Incom- 
plete combustion of the methyl-alcohol now ensues, and in consequence 
gaseous formic aldehyde is copiously developed, the vapour being dis- 
charged at a high pressure. The apparatus is said to work very 
efficiently, and to be superior to Tollens’ lamj), as the amount of air is 
easily regulated, and the stream of gas can be directed with ease against 
any particular point. The apparatus was used for disinfecting small 
infected articles and large spaces. 
Cocain in the Study of Pond-Life.* — Mr. H. N. Conser calls 
attention to the special value of hydrochlorate of cocain as a narcotic 
in the study of Bryozoa and the encased Rotifera. Quick-killing 
methods cannot be used where the contractile organs are so well pro- 
tected as in these forms, neither can the narcotics that kill, for they 
allow disorganisation of the tentacles before other parts of the organisa- 
tion are sufficiently benumbed. The method the author has found most 
satisfactory and certain is as follows : — Several colonies of Bryozoa are 
placed in a solid watch-glass with 5 ccm. of water, and as soon as the 
animals have expanded, one or two centigrams of cocain are dropped on 
the edge of the water at two or three distant points ; in 15 minutes the 
narcotic influence is sufficient, as can be tested by touching the tentacles 
with a needle. One per cent, chromic acid is now poured in to fill the 
watch-glass, and left to act for half an hour or more, when it is nearly 
all withdrawn, and water substituted. This process is repeated in half 
an hour, and alcohol to form about 25 per cent, added to the water. 
The strength of the alcohol must be increased until 80 per cent, is 
reached. By this means the chromic acid is washed out, and the 
hardening accomplished so gradually that no distortions occur. Swim- 
wing Rotifers readily succumb to the influence of cocain, but the 
Melicertidae hold out for a long time against it. The method for these 
is like that for the Bryozoa, with the exception that only sufficient 
water to cover the colony well need be used. The quantity of cocain 
must be relatively large, and, when all movements cease, killing may 
be done with 20 per cent, formalin, for chromic acid precipitates cocain 
when present in any considerable quantity. 
Separation of Vegetable Acids.f — M. L. Lindet recommends the 
use of methyl-alcohol for the separation of citric and malic acids in 
plants, after treating with quinine. In the cold, methyl-alcohol of 95° 
per cent, dissolves 8 • 2 per cent, of the acid malate of quinine, but only 
0 * 3 per cent, of the acid citrate of quinine. 
Microscopical Examination of Cosmetics.^ — Herr G. Marpmann 
gives an instance of the value of microscopical examination. Two 
samples of almond paste were submitted to him. One was found to 
contain two-thirds of fine siliceous earth, the other one-third of an 
* Amer. Mon. Micr. Journ., xvii. (189G) pp. 95-6. 
t Coraptes Rendus, exxii. (1896) pp. 1135-7. 
f Zeitschr. f. angewandte Mikr., ii. (1896) pp. 10-11. 
