442 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
which the body of the Microscope is vertical, for photographing objects 
in liquids, is figured. The procedure of developing the photographic 
plates is described. 
Fig. 43. 
B. Technique.* 
(1) Collecting- Objects, including- Culture Processes. 
Plankton-Methods. — Prof. J. Frenzel j discusses at some length the 
merits and demerits of the silk-gauze net. Even the details of the block- 
ing of the gauze come to have importance in exact quantitative estimates 
of the Plankton. He recommends repeated use of hot water for cleaning 
the net, which he regards as fully useable when it remains constant in 
hot water. 
Prof. Y. Hensen t also discusses the use of the silk-gauze net. To 
free it from adhering particles which tend to close the pores, the best 
plan is to rub it under water with a bath-sponge. This is much better 
than boiling, which Frenzel recommended. 
Medium for differentiating the Bacillus typhosus from Bacterium 
coli commune.§ — Dr. K. Kashida recommends the following medium for 
easily distinguishing between Bacterium coli commune and the bacillus 
* This subdivision cod tains (1) Collecting Objects, including Culture Pro- 
cesses ; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes ; 
(4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, &c. ; 
^ M i cnol Ion onn a 
t Biol. Centralbl., xvii. (1897) pp. 364-71. % Tom. cit., pp. 540-42. 
§ Centralbl. Bakt. u. Par., l te Abt., xxi. (1897) pp. 802-4. 
