344 SUMMARY OF CURRENT RESEARCHES RELATING TO 



following simple manner :— Weigh out 800 to 1000 grms. of snails, and 

 boil slowly for a half to three-quarters of an hour in one litre of water. 

 The body of the animal can then be easily extracted from the shell. 

 Filter by squeezing through a cloth. Add ten grms. of pepton and 

 five grms. of salt. "The liquid is naturally neutral, or slightly alkaline^ 

 so that it is unnecessary to alkalinize. Sterilize in the autoclave. Filter 

 cold and re-sterilize. The bouillon is transparent, and of a slightly 

 brownish-yellow colour, and can be incorporated with gelatin or agar in 

 the usual way. By reason of its smaller albuminoid content this media 

 is slightly inferior to those having a beef basis, but is, nevertheles?. 

 clearly superior to the media prepared with pepton alone. In the 

 actual conditions of practical bacteriology in the field it is undoubtedly 

 economical, and is suitable for all ordinary laboratory use. 



Vegetable Broth as a Culture Medium.* — A. Berthelot states that 

 the following medium has given good results in his bands. The 

 formula and mode of preparation is as follows : — Water, four litres ; 

 potatoes, 300 grms. ; carrots, 150 grms. ; turnips, 150 grms. Peel the 

 potatoes (" Holland or de Yitlette," for preference) and divide them in 

 two; wash the carrots and turnips, and cut them in slices of about 

 1 c.cm. thick. Place the vegetables in a marmite of enamelled iron 

 containing four litres of cold water. Boil for four hours, and filter 

 through a fine cloth. The quantity of liquid should be reduced to three 

 litres by the boiling process. If the concentration has gone too far, add 

 a sufficiency of distilled water to make the volume up to three litres. 

 Made feebly alkaline to litmus with ^V soda solution, autoclave at 120''C. 

 for half an hour, leave in the ice-chamber for twenty-four hours, and 

 then filter through filter-paper. Sterilize afresh lor twenty minutes at 

 115°C. The resulting liquid should be limpid, and of about the same 

 colour as ordinary meat-broth. A large number of bacterial species, 

 saprophytic and pathogenic, grow more or less abundantly in this, 

 medium. For growth of yeasts and bacteria that cannot multiply in 

 alkaline media, the broth should be left at its original reaction, which is 

 generally feebly acid to litmus. It is stated that pathogenic organismB 

 crown on this media have a minimum of toxicity, and are thus- 

 eminently suitable for the preparation of vaccines. 



Culture of Spircchaeta ictero -hsEmorrhagica.t — L. Martin 

 A.Pettit, and A. Vaudremer find that the media which give the best 

 cultural results with Spirochseta idero-liaemorrhagica are as follows: — 

 1. "Serum de boeuf-eau physiologique." Dilute 1 c.cm. ox serum 

 heated to 50° C, in 9 c.cm. salt solution (0 • 89 p.c). Inoculate with 

 heart blood or liver pulp, and cover with vaseline. Incubate between 

 23° and 33° C. The maximum growth of spirochetes occurs towards 

 the tenth day. Growth ceases in about three weeks. 2. "Serum de 

 lapin-eau physiologique." Dilute 1 c.cm. rabbit serum in 5 c.cm. salt 

 solution (0-89 p.c.) and proceed as above. The first cultures develop. 



* C.R. Sec. Biol. Paris, Ixxx. (1917) pp. 131-2. 

 t C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 197-200. 



