426 SUMMARY OF CURRENT RESEARCHES RELATING TO 



only precautions necessary are to sow copiously and incubate at once. 

 The casein from a litre of milk is precipitated by means of 2 c.cm. of 

 hydrochloric acid and then filtered off, the filtrate being neutrahzed with 

 normal sodium hydrate. To this is added an equal bulk of 2 p.c. pepton 

 water, enriched with 1 p.c. saccharose and * 35 to 4 urea. A jelly is 

 then made with 1 • 6 p.c. agar. After sterilization and filtration the 

 medium is distributed in tubes and then sterilized afresh. 



Method of Growing the Acne Bacillus.* — T. H. C. Benians gives 

 the following procedure for cultivating the l)acillus of acne from the 

 comedo for the preparation of vaccines. A comedo is expressed into a 

 sterile glass tube of small bore, the edges of which have been pre- 

 viously rounded-off in the flame. The comedo is dropped into a tube 

 containing neutral broth, which is then covered with a layer | in. thick 

 of sterilized olive-oil or lard. The comedo should be made to sink to 

 the bottom of the tube. In 24 to 48 hours the medium becomes turbid 

 from the presence of Stcqjhylococcus aJbtis, while in 3 or 4 days the 

 growth of acne bacillus is seen at the bottom and sides of the tube as a 

 granular deposit. At the end of about 10 days films show a relatively 

 few cocci and largfe masses of bacilli. 



(2) Preparing- Objects. 



Fixing" the Pseudopods of Foraminifera.f — H. Reschad places the 

 Foraminifer (Jliliolina) in a hollow ground slide, letting it lie in a 

 moist chamber until the pseudopoda are well extended. When this has 

 happened the slide is immersed, rapidly and deftly, in the following 

 dilutions of alcohol (5, 10, 20, 35, 60, 80, 95, 99*8 p.c). After the 

 last the preparation is immersed in Schaudinn's sublimate-alcohol for 

 10-15 minutes. 



Much skill and care are required to prevent the Foraminifer from 

 being washed off during manipulation. It is recommended to immerse 

 the slide on that side towards which most of the pseudopods are directed. 



The preparations may be stained in Giemsa (4 drops to 1 c.cm. of 

 water) renewed every 3 minutes during a quarter of an hour. The pre- 

 paration is then washed with distilled water and afterwards with tap- 

 water. 



Then follow alcohol, carbol-xylol, and balsam. 



Simple Histological Methods J— J. Salkind gives an account of 

 certain procedures, by the adoption of which histological manipulations 

 may be simplified. 



Sublimate Fixation. — The troublesome part of this process is the 

 iodine treatment, required to remove the precipitate of mercury salts. 

 If, after fixing in Zenker's or Helly's fluid, the material is placed in 

 a solution containing 3 p.c. potassium l)ichromate and 1 to 2 p.c. hydro- 

 chloric acid — or, as an alternative (where acid solutions are undesirable) 



* Lancet, 1913, 1. pp. 1801-2. 



t Zeitschr. wiss. Mikrosk., xxix. (1913) pp. 526-7. 



+ Zeitschr. wiss. Mikrosk., xxix.'(1913) pp. 540-4. 



