623 SUMMARY OF CURRENT RESEARCHES RELATING TO 
phenomena of diffraction, all afford interesting subjects of study. As 
regards the stage, the size and form best adapted for various purposes 
have to be considered. The relative advantages of small and largo 
instruments have to be determined. The author refers those who say 
that the largest English instruments cannot be conveniently used in an 
upright position to Dr. Dallinger’s method of using his Powell and 
Lealand upright, as illustrated in the new edition of Carpenter. 
The author considers that all sound reasoning and practical ex- 
perience agree in sustaining his proposition “ that systematic and 
thorough training in the use of the Microscope is highly desirable, and 
that the University is the school to which we naturally look for the 
means to meet the want.” 
Stereoscopic Vision applied to Diatoms.* — Count A. F. Castracane 
points out the utility of binocular stereoscopic apparatus in microscopic 
observation and photography, particularly in relation to diatoms. He 
suggested and practised this manner of observation twenty years ago,, 
but his example does not seem to have been followed, until recently — 
by Dr. G. Fritsch and 0. Muller. 
B. Technique.! 
Cl) Collecting 1 Objects, including Culture Processes. 
Apparatus for Anaerobic Cultivations.^: — Herr W. Lubinski de- 
scribes some apparatus which he has devised for the cultivation of 
anaerobic micro-organisms. 
The first apparatus consists of a glass jar A, 25-28 cm. high ancl 
15-17 cm. diameter, the upper part of which is expanded as shown in 
fig. 71 at B. Into A is fitted the part C which is provided with a sort of 
flange, perforated with two openings placed opposite one another. The 
part D is also provided with two openings, and a handle serves as a 
cover. When required for use a rubber tube is fitted on to the opening 
a! of the part C ; this reaches to the bottom of the jar. The culture- 
tubes all having been arranged in jjosition, the cover D is put on, so 
that the openings l and m abut against those of the part C* All the- 
cracks and joins of the apj>aratus must be smeared up with vaselin. Gas 
is introduced into the jar by the openings l or m, according to the spe- 
cific gravity, if heavy through m, if light through l. When all the air 
has been driven out, a turn of 90° is given to the lid D. In order to 
prevent any diffusion of gases, the expanded portion of the jar which 
acts as a reservoir is filled with water. During incubation it is advi- 
sable to put a weight on the lid to prevent it being raised by the in- 
creased gas tension, though this may be avoided by filling the jar with, 
warmed gas. 
Another apparatus, fig. 72, is a glass jar of similar size to the last,, 
and closed by a glass stopper. At opposite sides of the jar are two- 
tubes, to which are adapted bulbs, something like Woulf’s bottles, t x 
for the introduction of gas, t 2 for the exit of air. These bulbs are par- 
tially filled with fluid paraffin or vaselin. The upper bulb in t 2 is to 
* Atti Accad. Pontif. de’ Nuovi Lincei, xlvi. (1898) pp. 145-8. 
f This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses; (2) Preparing Objects ; (8) Cutting, including Imbedding and Microtomes; 
(4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, &c. ; 
(6) Miscellaneous. 
+ Centralbl. f. Bakteriol. u. Parasitenk. xvi. (1894) pp. 20-5 (4 figs.). 
