11" SUM MARA 7 OF CURRENT RESEARCHES RELATING TO 



sand as follows : in 150 c.crn. Erlenineyer's flasks, 10-15 grm. of sand 

 are placed, together with 20 c.cm. of the specific liquid-culture medium. 

 The whole is then sterilised, after which the flasks may be inoculated. 

 For inoculation purposes, 1 c.cm. of a heavy suspension of Azotobacter in 

 sterile water is used. After inoculation the sand is so sloped that a 

 considerable quantity is above the surface of the liquid culture medium. 

 This slope thus furnishes a solid substratum always well saturated with 

 the culture solution due to capillary action. It further affords optimum 

 aerobic conditions essential for the luxuriant growth of Azotobacter. 



Cultivation of Spirochseta gracilis and S. balanitidis.* - -('. 

 Levaditi and V. Stanesco cultivated these Spirochetes — the one derived 

 from a chancre, the other from the pus of balanitis — by sowing the 

 microbic flora in a large tube containing horse serum, and three days 

 afterwards inoculating the Spirochetes in a collodion sac filled with 

 horse serum placed within the large tube. In this way the nutritive 

 substances prepared by the microbic flora penetrate the sac, and assure 

 the multiplication of the Spirochetes. Another method was to make 

 stab-cultures in horse or human serum coagulated at 75°. Both these 

 methods produced cultures extremely rich in Spirochetes. These 

 organisms are, however, incapable of assimilating the nutritive substances 

 of the serum without the co-operation of the associated microbes, which 

 are essentially proteolytic. It is only on the third or fourth day after 

 liquefaction of the medium has commenced that Spirochseta gracilis and 

 S. bala nitidis begin to multiply. Thus by making use of a liquefying 

 aerobic bacillus the authors obtained mixed cultures, in which S. gracilis 

 multiplied in symbiosis with the bacillus. In this connection it may be 

 pointed out that there is a certain analogy between the culture conditions 

 of Spirochete and Amoebae. 



Cultivating Meningococcus.! — P. Esch made comparative observa- 

 tions with maltose-ascites-agar, Lceffler's and Buchanan's serums, and with 

 sheep's-blood-maltose-ascites-agar. The last was found to give constant 

 results, and the growth on this medium was very rapid and luxuriant. In 

 from 8 to 12 hours the colonies were evident, and in one instance a 

 vaccine was obtained in 24 hours. The medium consists of 60 c.cm. 

 pepton agar (1 p.c. pepton Witte) : to which, after cooling to about 

 50° C, are added 20 c.cm. sterile defibrinated sheep's-blood. 10 c.cm. 

 ascitic fluid, and 1 grin, maltose dissolved in 3 c.cm. bouillon. 



Detection of Bacteria by means of an Electric Current. J — 

 C. Kuss made experiments to ascertain whether bacteria, suspended in 

 an electrolyte, through which a current passes, are transmitted to 

 either electrode, and if so, whether pathogenic organisms could be 

 collected and extracted by such means from pathological fluids. He 

 found that certain bacteria, under the influence of a suitable current, 

 aggregate at one or other electrode. The aggregation varies with the 

 nature of the electrolyte, and is probably due to affinity between the 

 products of electrolysis and the bacteria. The aggregation by electrical 



* G.R. Soc. Biol. Paris, lxvii. (1909) pp. 188-90. 



t Centralbl. Bakt., lte Abt. Orig., lii. (1909) pp. 150-1. 



% Proc. Roy. Soc, Series B., lxxxi. (1909) pp. 314-22 (3 figs.). 



