(c) Constancy in composition of medium: To insure absolute constancy 

 in the composition of the medium a stock infusion was prepared from one 

 large shipment of fresh hashed liver (200 pounds). This was estimated 

 as the quantity large enough to cover the needs of the entire investigation. 



2. CULTURES: 



(a) Preparation of cultures for mass growing: Jablons liver peptone 

 broth (58) was used for the cultivation of the test organisms preliminary 

 to mass growing. This medium attracted our attention because it 

 contained the same ingredients as the solid medium selected, thus 

 favoring exceptional uniformity in the metabolic reactions of the bacteria 

 throughout the entire experimental period. That the bouillon supported 

 hardy development may be proven by the following experiments com- 

 paring it with other good liquid media: (i) Huntoon broth (56) and (2) 

 Rosenow broth (59). The test media were inoculated with one loopful 

 of culture from the seed tubes, kept at room temperature for 60 hours 

 and then incubated for 24 hours at 37 C. Tests were made on 50 strains 

 of streptococci. A comparison of the amounts of growth in the different 

 preparations will give convincing proof that Jablons medium favors rapid 

 growth of the organisms under consideration. The results tabulated 

 represent the reactions given by all the organisms. 



At regular intervals transplants to glucose blood agar were made, 

 incubated for 24 hours at 37 C. and examined for growth. If growth was 

 slight or doubtful, subcultures were made to confirm the results. By 

 this procedure further evidence was obtained regarding the quality of 

 the liver broth. A mere glance at the following summary shows that, in 

 addition to supporting very rapid growth, Jablons medium also supports 

 very prolonged viability. 



These results place each medium in the order of preference for the 

 cultivation of streptococci, if longevity without transplant is taken as 

 the criterion. With four weeks as the limiting period no differences are 

 noticed; the three preparations match each other exactly. But, more 

 prolonged viability necessarily infers less interference with normal 

 metabolism. This makes Jablons medium the most efficient since it is 

 so constructed as to give the organisms the greatest chance for continued 

 vitality. 



After growing the organisms in this broth for one month, 0.05 c.c. 

 was transplanted to liver agar plates and grown at 37 C. for 18 hours. 

 From this two successive subcultures to solid liver medium were made on 

 two consecutive days. The last culture served as the seed culture for 

 mass planting. 



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