392 SUMMARY OF CURRENT RESEARCHES RELATING TO 



solution (28-6-100) 5 ccm. ; distilled water 1000 grm. The Heyden's 

 aliment is first dissolved in water, and then the agar-rnixture con- 

 taining the rest of the ingredients is added. The medium is filtered 

 while hot, through a special apparatus. On this medium tubercle bacilli 

 are said to be demonstrable from sputum after a few hours' incubation, 

 and it is claimed that the procedure obviates the necessity of testing 

 doubtful secreta in animals. 



Effect of Varieties of the Medium on the Growth of the Typhoid 

 Bacillus.* — Prof. E. J. McWeeney states that the experiments made by 

 him on the effect of certain varieties of the nutrient medium on the 

 growth of the typhoid bacillus show that : — (1) the growth improved with 

 increasing addition of decinormal sodium hydrate to the unneutralised 

 gelatin up to the beginning of alkalinity (indicator phenolphthalein) ; 

 (2) the addition of salt in quantities varying from ■ 1 to 1 per cent, to 

 the fully neutralised gelatin made no difference in the amount of 

 growth ; (3) the omission of both salt and pepton exercised no appre- 

 ciably unfavourable influence on the growth in gelatin made with 

 meat decoction ; (4) addition of phenol to gelatin in the proportion 

 of • 05 to 0*5 per cent, exercised an inhibitory influence on all 

 growths when the addition exceeded 0*07 percent.; between 0*05 

 and • 07 the effect was to check the anaerobic growth ; and (5) Pari- 

 etti's solution added to ordinary bouillon suppressed the growth of the 

 typhoid bacillus when the bacillus coli was also present. 



Culture and Demonstration of Amcebae.f — Herr G. Marpmann 

 points out that pathogenic amoeba? are easily cultivable in the animal 

 body, guinea-pigs and rabbits forming suitable hosts. Artificial cultures 

 of earth, water, and intestinal amoeba? are obtainable only when the 

 medium resembles the natural environment and when the temperature is 

 normal. • A good medium consists of agar • 6, hay infusion 100, alkaline 

 bouillon 10 parts. On this medium the mixed colonies of bacteria and 

 amoeba? will be found in about twenty-four hours after inoculation. 

 Without the presence of living bacteria amoebae do not grow, and if the 

 bacteria be killed off by means of alcohol or strong soda solution, they 

 remain encapsuled and do not develope further. 



Other media which may be recommended are: — (1) Hay or straw 

 decoction, 30-40 grm. boiled for half an hour in 1 litre of water, filtered, 

 and alkalised with carbonate of soda. (2) Hay or straw-agar. The 

 foregoing decoction with the addition of 1*5 per cent. agar. (3) Fucus 

 crispus substratum. A 5-15 per cent, solution of fucus in water or 

 bouillon is boiled, mixed with 10 per cent. 1/10 normal caustic potash 

 solution, filtered, and analysed. (4) Agar-medium : — agar 0*5, water 90, 

 alkaline bouillon 10; boil, filter, sterilise. 



The cultivation of blood amoeba? and of malaria and leukha?mia 

 parasites has not yet been effected on artificial media, probably owing to 

 the fact that as they are cell-parasites, a dead medium is insufficient 

 for their wants. They are, however, cultivable in. animals, as has been 

 recently shown by Lowit, who injected rabbits with a mixture of leuk- 

 ha?mic blood, ascitic fluid, and blood drawn from the finger. 



* Eoy. Acad. Med. Ireland. See Lancet, 1900, i. p. 939. 

 t Zeitschr. f. angew. Mikr., v. (1900) pp. 325-38 (7 tigs.). 



