ZOOLOGY AND BOTANY, MICIIOSCOPY, ETC. 499 



MICROSCOPY. 



B. Technique.* 

 lli Collectina: Objects, including- Culture Processes. 



Whey Medium for the Gonococcus.f — T. Watabiki, after long ex- 

 perience witli the cultivation of the gouococcus, maintains that blood - 

 agar and blood-bouillon are the most suitable media for growing 

 gonococci. When, however, blood cannot easily be obtained for the 

 purpose, whey-agar or whey-bouillon may be used as sulistitutes. 

 100 c.cm. fresh milk is warmed to 60° C, and 5 p.c. acetic acid added 

 drop by drop, the milk being shaken to cause precipitation of the 

 casein ; it is then filtered through filter-paper. To the filtrate 10 p.c. 

 caustic soda solution is added up to the point of slight alkalinity to litmus- 

 paper, and then 9 '3 grm. nutrose and 0'2 grm. urea (previously 

 dissolved in a little boiling water). The clear colourless fluid is then 

 sterilized by keeping at 60° C. for thirty minutes every day for three 

 days. Next, this sterilized fluid is well mixed with melted agar medium 

 (2-5 p.c.) at 45° C, in the proportion of about 1 part of fluid to 2 parts 

 of agar, and then plates of slopes are prepared as required. It is 

 necessary that the fluid should not be heated above 70° C. The author 

 has frecpiently noticed unsatisfactory results with fluid heated at a 

 higher temperature. Urea is not necessary, though its presence seems 

 favourable. For the precipitation of casein the amount of acetic acid is 

 not constant, as different samples of milk undoubtedly vary in quality. 

 About the same percentage of urea was added as that in normal urine 

 (20 to 25 grm. urea in 1000 c.cm. urine). 



Experimental Typhoid Septicsemia by Means of Bile Cultures. | 

 M. le Fevre de Arric has devised a method of exalting the virulence of 

 a virulent typhoid bacilli by means of bile cultures. The original 

 culture employed was of such a low degree of yirulence that 10 c.cm. 

 of a 24-hour broth culture injected under the skin of a 400-grm. 

 guinea-pig did not provoke any symptoms. When, however, the 

 cultures were made in sterilized ox-bile, and after forty-eight hours in- 

 jected into guinea-pigs of similar weight, the animals succumbed in less 



* 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, etc. ; 

 (6) Miscellaneous. 



t Journ. Path, and Bact., xx. (1916) pp. 408-9. 



i C.B. Soc. Biol. Paris, Ixxix. (1916) pp. 602-4. 



