ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
445 
out to a point at the lower end. When the material is ready for wash- 
ing, a fine-meshed cloth is stretched over the mouth of the bottle and 
field in place by a rubber band. The bottle is then placed beneath 
the trough, and one of the tubes lowered until the pointed end projects 
through the cloth into the bottle. The water passes off through the 
meshes of the cloth. A convenient size for the trough, which may be 
made of tin, is 6*25 cm. deep by 8 "75 cm. by 29 5 cm., so as to fit 
the ordinary sheet of insect cork. The space beneath is 7*5 cm. high. 
The cork should be at least 1 cm. thick. The holes are 1 • 8 cm. from 
the edge and 3*75 cm. apart. This will allow of eighteen 25 mm. 
bottles being washed at once. The glass tubes are 6*75 long with an 
inside diameter of 3 mm. 
New Preservative Method for Plankton Flagellata.* — Herr 0. 
Zacharias succeeded in fixing Uroglsena balls in a mixture of two 
volumes saturated boric acid solution and three volumes of saturated 
sublimate solution so satisfactorily that they were afterwards preserved 
in dilute formol or alcohol without detriment. To the freshly taken 
plankton was added about one-third its bulk of the mixture, and after 
about three hours the material was carefully washed on a gauze filter. 
The material was finally preserved in 2 per cent, formol or in 50 per 
cent, alcohol, afterwards changed to 70 per cent. 
The same method may be adopted if Dinobrya be in the plankton 
catch. 
Diatoms and Loricata are well fixed by the mixture, but it is not 
advisable to use it for small Crustacea. The latter are better treated 
with chromacetic acid. 
Gaylord’s New Apparatus for Liquid Filtration by Gas Pressure 
through Bacterial Bougies. f — Dr. H. B. Gaylord, of Buffalo Uni- 
versity, describes his apparatus as an improvement and modification of 
Given and Campbell’s, described in 1895 ; it also resembles D’Arson- 
val’s. The application of air pressure has the advantage that the liquid, 
after filtration, is led into a vessel, out of which the gas (C0 2 ) given off 
through the bougie can immediately escape. As the gas escapes out- 
wards from within, the entrance of bacteria-laden air is rendered 
impossible. 
The apparatus (fig. 110) consists in its upper part of a wide chamber 
for the reception of the liquid to be filtered ; while in the lower part, 
containing the bougie, it is narrower. The material is copper, and its 
pressure resistance about 300 lb. The pressure is applied from a 
cylinder charged with carbonic acid ; and the apparatus is adapted for 
Pasteur’s and Borkfeldt’s bougies of the usual size. The bougie B 
has its exit at b , and is surrounded by a caoutchouc tube c ; D is the 
caoutchouc Pasteur stopper ; the flask C has a doubly bored stopper, 
the tube c passing through one of the openings, and a plug of wadding 
closing a glass tube inserted in the other. The glass tube on which 
c is fitted is kept in its place and firmly clamped by the ring F. There 
is sufficient space between E and the end of the filter, so that when the 
ring F is almost screwed up, the pressure on the stopper D at d l becomes 
* Zool. Auzeig., xxii. (1899) pp. 70-2. See Zeitsclir. f. wiss. Mikr., xvi. (1899) 
pp. 67-8. t Zeitschr. f. wiss. Mikr., xv. (1899) pp. 427-32 (5 figs.). 
