98 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
legs. The revolving top can, when desired, he clamped by a separate 
hand clamp. 
Illustrated Annual of Microscopy.* * * § — Among other interesting 
articles in this Annual may be mentioned especially : — 
£ Achromatics and Apochromatics,’ by E. J. Spitta. A very interest- 
ing popular account of these lenses. 
‘ Elementary Theory of the Microscope/ An excellent treatise by 
Mr. Conrad Beck ; contains a treatment of microscopical optics on the 
methods of Gauss. 
B. Technique. f 
(1) Collecting: Objects, including* Culture Processes. 
/ 
Apparatus for Anaerobic Cultivation..]: — Herr L. Zupnik has devised 
an apparatus by which a perfect vacuum is secured. The main part of 
the apparatus is a cylindrical glass vessel K (fig. 18) having narrow 
tubes at both ends which can be closed by stop-cocks H 1 and H,. The 
culture vessel is completely filled with a nutrient solution, and after 
inoculation the tap H x is closed. To the lower end is now fitted on, 
through the intermediary of a rubber joint Sch, a thick glass tube R 
80-90 cm. long. The apparatus is now reversed, and the tube R com- 
pletely filled with mercury. The end of the tube having been closed 
with the finger, and the apparatus restored to its former position, it is 
now plunged into a vessel W filled with mercury. 
On removing the finger the mercury sinks, and a Torricellian 
vacuum is produced. The tap H 2 is now opened, the medium flows down, 
leaving an airless space above. After closing H 2 the tube R is removed 
and the apparatus placed in the incubator. According to the length and 
width of the tube R, any desired quantity of medium can be removed. 
In this way quite a large space may be left above the level of the culture 
medium. This serves for the collection of any gas required for chemical 
examination. 
Apparatus for Cultivating Anaerobic Bacteria. § — Dr. S. Epstein 
describes an apparatus which he has used with success for a considerable 
period. As shown in the illustration (fig. 19), it consists of an Erlen- 
mayer’s flask A closed by a perforated rubber plug B. Into the perfora- 
tion is inserted a glass tube exj)anded above at G and provided with a 
Bunsen’s air-valve L. On the expanded portion of G rests a bell-jar T. 
The flask is filled with the medium, and the latter inoculated. The rubber 
plug is then pushed home. This causes the medium to rise in the tube as 
far as the valve. The air-valve L is made out of a piece of caoutchouc 
tubing by snipping it at V with scissors and thus forming an angular 
(<) valve. The bell-jar is filled with a 2 per cent, boric acid solution, 
so that the valve lies below the level of the fluid. The gases from the 
* London, P. Lund Humphries & Co., Limited, 1898. 
f This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses; (2) Preparing Objects ; (3) Cutting, including Imbedding aud Microtomes; 
(4) Staining and Injecting; (5) Mounting, including slides, preservative fluids, &c. ; 
(6) Miscellaneous. 
J Centralbl. Bakt. u. Par., l te Abt., xxiv. (1898) pp. 267-70 (1 fig.). 
§ Tom. cit., pp. 266-7 (1 fig.). 
