ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
371 
is to be worked at 112°, the water-holder is filled up to the level in- 
dicated, the tap a is closed, and R left open until the thermometer 
reaches 98°— 99°, a point which indicates that all the air has been driven 
out of the apparatus. The tap t R is then turned, and the temperature 
soon rises to 112°. Should the temperature and pressure rise above this, 
the steam escapes through the safety valve. 
By a preconcerted adjustment of the tap R, the valve V, and the 
flame F, a temperature constant between 100° and 112° can be main- 
tained. 
B. Technique.* 
Cl) Collecting- Objects, including: Culture Processes. 
Aseptic Cultivation of Mycetozoa. j — Dr. C. 0. Miller, who described 
a method for the cultivation of Protozoa,! finds that some modifications 
are necessary for Mycetozoa. They will grow in sterilised dilute hay 
infusion, or 2 per cent, of milk in water; but for the formation of 
sporanges it is usually advantageous, and sometimes essential, to furnish 
the organisms with a mechanical support as a means of getting out of 
the water. The medium is prepared by putting a handful of hay in a 
jar and washing it until the water remains colourless. It is then covered 
with fresh water, and allowed to soak overnight. The following day 
the water is poured off, filtered, diluted with fresh water until it is of 
a white wine colour, and 2 per cent, of milk added. It is then filtered, 
put into a flask and sterilised for future use. The macerated hay is 
cut, and placed in Erlenmeyer’s flasks ; the first portion is cut short 
enough to form a tolerably compact layer at the bottom of the flask 
to the depth of 1 cm. ; the rest is cut sufficiently long to form a very 
loose layer, reaching about two-thirds the way up the sides of the flask, 
care being taken not to allow any of the stems to reach the cotton. 
Sufficient water is placed in the flasks to cover the hay, and they are 
sterilised for 15 minutes. On the following day fresh water is sub- 
stituted, and they are again sterilised. The water is once more poured 
off, and enough of the hay infusion and milk previously prepared is 
added until it is about 1 cm. deep. The flasks are then sterilised for 
10 minutes on three successive days. They are then ready for use. 
The cultures are usually transplanted by means of a sterilised 
pipette. 
Peptonised Milk for the Cultivation of Lactic Acid Ferments. § — 
Herr 0. Jensen, who confirms the opinion of Kayser as to the excellence 
of peptonised milk as a medium for cultivating lactic acid bacteria, gives 
the following method for its preparation. 
After the milk is sterilised, 10 ccm. per litre of pure hydrochloric 
acid and 2 grm. of pepsin are added, and the mixture incubated at 
35°-37°. At first, until the casein is separated and the pepsin dissolved, 
the flask is to be frequently shaken up, but afterwards this need only 
be done occasionally. 
* This subdivision contains (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. ; 
(6) Miscellaneous. f Quart. Juurn. Micr. Sci., xli. (1898) pp. 46-9 (2 pis.). 
t Cf. this Journal, 1894, p. 744. 
Centralbl. Bakt. u. Par., 2 t8 Abt., iv. (1898) pp. 196-9. 
