ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
693 
for evaporating down nutrient media so as to avoid the danger of 
exposing the fluid to contamination during the process. The apparatus 
will evaporate a watery fluid at a temperature of 23° to dryness in quite 
a short time, and keep it germ-free; it consists of two parts : a 
conical glass vessel holding 3-4 litres ; in the base, which is upper- 
most, are two openings, and the apex of the cone is also open ; all 
three openings can be closed with caoutchouc plugs. This vessel is 
placed inside another made of brass and of similar shape. The latter 
is supported on an iron stand, and is fitted with glass windows for 
observing the evaporating fluid, a thermometer, and a thermo-regulator. 
Besides the foregoing are required caoutchouc plugs, bent glass tubes, 
a Chamberland’s filter, Wolff’s bottles, with a manometer, a Liebig’s 
cooler, and a water suction pump. 
The arrangement of the apparatus is shown in fig. 82, and after all the 
various parts have been carefully sterilized, the glass vessel A, with its 
three openings closed, is placed inside the metal case B. Above the 
opening 3 is a firm rubber valve. The plugs are then removed from 
2 and 3, and these apertures connected with D the filter and G the 
cooler. The other end of G the cooler is in its turn connected with the 
water pump J through the mediation of the Wolff’s bottles IDH 2 . 
The water-tap is now turned, and the pump beginning to act, 
exhausts the air from the apparatus. The fluid to be filtered is then 
poured into the filter, and in about seven minutes the first drops begin 
to fall into A. As soon as the desired quantity is obtained, the process 
is stopped by the clamp L. The pan B is then filled with water and 
the burner N underneath lighted. The temperature of the water-bath is 
to be regulated for 38°. In twenty-four hours about two litres of fluid 
will have been filtered. 
This part over, air is allowed to enter by removing first the Chamber- 
land’s filter and replacing it by a glass tube constricted at one place and 
stuffed with cotton-wool. The screw L is then loosed and air, filtered 
through the cotton-wool, enters the apparatus. 
New Method for Ascertaining the Temperature of Sterilizing 
Ovens.* — On account of the difficulty of regulating the thermometer 
M. Quenu uses a small tube filled with an easily fusible mass for indi- 
cating the temperature of his sterilizer. Sulphur which melts between 
112° and 117°, benzoic acid, and an alloy of bismuth and tin which melts 
between 130° and 143° were found to answer best. The author states 
that the method is convenient but costly. 
Cold-sterilized Albuminous Nutrient Media.j — Dr. A. Reinsch 
makes milky nutrient media in the following manner. 500 ccm. of fresh 
cow’s milk mixed with 1 * 0 grm. of NaHO are well shaken up in a 
separator-funnel and then allowed to stand for 48 hours at a temperature 
of about 18°. At the end of this time the fatty matters are collected 
in a creamy layer on the surface of the fluid, the now pretty clear fluid is 
transferred to another filter and then shaken up with 250 ccm. of ether. 
At the end of 48 hours the ether has separated from the clear but 
slightly opalescent fluid. The latter still contains a considerable 
* La Semaine Med., 1892, p. 203. See Centralbl. f. Bakteriol. u. Parasitenk., xii. 
(1892) p. 40. t Centralbl. f. Bakteriol. u. Parasitenk., xii. (1892) pp. 30-2. 
