728 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and influenza, gonococcus and meningococcus, on a medium the mode of 

 preparation and composition of which is as follows. To 200 c.cm. of 

 4 p.c. glycerin-water are added 100 grm. of sliced potato ; by boiling 

 this mixture in an autoclave a glycerin-extract of potato is obtained. 

 To 50 c.cm. of this extract are added 150 c.cm. of 0*6 p.c. salt solution 

 and 5 grm. of agar (gelose). After melting it in the autoclave, the 

 potato-agar is distributed into test-tubes, about 2-3 c.cm. in each, and 

 then sterilised. 



Kabbit's blood (though human is preferable) obtained aseptically is 

 defibrinated, and to each tube, the agar being previously melted, is added 

 an equal quantity of blood. The tubes are well shaken, and then cooled 

 on the slant. 



As this medium does not contain pepton, it does not favour the 

 growth of putrefactive bacteria. 



Fish Tubercle grown at 37° C* — A. Aujeszky cultivated the fish 

 tubercle bacillus on potato dipped in 3 p.c. aqueous solution of glycerin, 

 and incubated at 28°-30° C. ; after six weeks, and at successive in- 

 tervals of six weeks, sub-cultures were made and incubated at gradually 

 higher temperatures, so that the fifth generation grew well at 37° C. ; 

 the cultures were now no longer white and moist, but yellow-grey to 

 brick-red, and resembling mammalian tubercle. The eighth generation 

 was fatal to a guinea-pig after 63 days ; control experiments with fish 

 tubercle grown at room temperature were without effect. 



Bacterioscopic Analysis of Excremental Pollution.f — E. Klein 

 insists that B. coli communis is the typical microbe of sewage and 

 ■excremental matter. MacConkey's medium makes no selection between 

 typical and atypical B. coli, nor does it exclude other microbes capable 

 of producing acid and fermenting glucose. The principal differential 

 character of B. coli communis is its power to ferment lactose. The 

 author inoculated, with high dilutions of sewage, human fsecal matter, 

 fluid from shell-fish, from polluted layings, and also from clean layings, 

 in parallel series, tubes of ordinary MacConkey medium, and MacConkey 

 medium made with lactose instead of glucose. The results showed 

 that whenever the lactose MacConkey tubes showed redness and gas 

 after 24-48 hours at 37° C, subsequent sub-cultures proved the presence 

 of typical B. coli communis ; whereas in a number of cases, after redness 

 and gas in ordinary MacConkey tubes, subsequent sub-cultures failed to 

 show the typical B. coli communis ; when the lactose MacConkey tubes 

 remain unchanged or become bleached and without gas, it is certain that 

 B. coli communis is not present, although in the glucose MacConkey 

 tubes, redness and gas have been produced. 



Taurocholate broth (5 c.cm. of 5 p.c. solution of sodium tauro- 

 cholate to 400 c.cm. of broth) that shows turbidity and gas-formation 

 after 24-48 hours incubation at 37° C, is a certain indication of the 

 presence of typical B. coli communis. The author found also that this 

 medium allows the growth of fsecal streptococci, but inhibits the growth 

 of Streptococcus pyogenes and the streptococcus of saliva. 



* Centralbl. Bakt., l te Abt. Orig., xlii. (1906) p. 397. 

 t British Med. Journ., 1906, ii. p. 1090. 



