ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
131 
Nutrient Gelatin with High Melting-point.* — The three chief 
points to be carefully attended to in obtaining a gelatin medium with 
high melting-point are, says Prof. J. Forster, the height of the tempera- 
ture acting on the gelatin, the duration of the action, and the concentra- 
tion of the gelatin. In practice, this amounts to observing that the 
temperature should never exceed 100°, and should not be protracted 
longer than 40 minutes, and that the gelatin should amount to 5 per 
cent. ; for it was found by experiments conducted for the purpose that 
the melting-point of gelatin was lowered by protracted boiling, and by 
the greater amount of water in the medium. It was further determined 
that above 5 or 6 per cent, the melting-point was but little higher 
than at these amounts ; consequently on the whole it was more advan- 
tageous to compose the medium with 5 per cent. On these lines a 
nutrient gelatin is produced which, after standing for 24 hours, has a 
melting-point between 29° and 30° C. 
Capsule for Anaerobic Cultivation.! — Dr. M. Beck has devised a 
modification of Petri’s capsule which renders this apparatus useful as 
a moist chamber, and for the cultivation of anaerobic organisms. By 
giving an S-bfend to the flange of the cover, two furrows or grooves are 
Fig. 8. Fig. 9. 
produced, the upper one of which serves for the reception of water 
when the capsule is to be used as a moist chamber. By the addition 
of a couple of lateral tubes any gas can be introduced. When required 
for anaerobic cultures, the lower furrow is filled with paraffin and fixed 
to the edge of the capsule by mere pressure. In this way an air-tight 
chamber is produced. 
Seminal Fluid as a Nutritive Medium.*— Dr. A. Cantani, jun., 
obtained pure seminal fluid by removing the testicle and spermatic cord 
and squeezing out the fluid on to the surface of oblique agar. As the 
fluid was removed aseptically, sterilisation and antiseptic precautions 
were avoided. 
Testicular juice which was smeared over the surface of oblique agar 
was obtained by cutting through the testicle, and removing the juice 
with a platinum loop. The tubes were afterwards incubated for 10 
hours. 
Though most bacteria grew fairly well on the seminal media, only 
influenza bacilli gave really good results. 
Influence of the Reaction of the Medium on Bacterial Growth.§ 
— Herr M. Deelemann has made experiments for the purpose of ascer- 
* Centralbl. Bakt. u. Par , l te Abt., xxii. (1897) pp. 341-3. 
t Tom. cit., pp. 343-5 (2 figs.). % Tom. cit., pp. 601-4. 
§ Arb. a. d. K. Gesundkeitsamt, xiii. (1897) pt. 3. See Centralbl. Bakt. u Par 
1" Abt., xxii. (1897) p. 355. ’ 
K 2 
