568 



WILLIAM S. STURGES AND LEO F. RETTGER 



routine production of heavy growths of this organism. Thirty- 

 liters of this medium distributed in 3-liter bottles were inoculated 

 from young broth cultures with the aid of a pipette, and incu- 

 bated at 37°C. for fifteen hours, by which time a fairly luxuriant 

 (about nephelometer 3) growth had developed. The broth 

 culture was then run through a Sharpless laboratory centrifuge 

 at a speed of 30,000 revolutions per minute. This separated 

 out the bacterial cells in the form of a viscid paste, which was 





CONDUCTMTy 



l'lS\ SdcPRCSXD in KOPROdAL OHnS 



11^ " 





BIIMI 



T 



Chart 11. Pneumococctts 



scraped into a sterile, wide-mouthed, glass-stoppered bottle. 

 About 17 grams of material were obtained which had a moisture 

 content of 80 to 90 per cent. The bottle was packed in a freezing 

 mixture and the contents kept near the freezing point for three 

 days, until the experiments could be started. The bacterial 

 paste w^as then divided into four parts and treated as follows : 



la. 0.55 grains suspended in 25 cc. physiological saline 

 lb. 1.0 grams suspended in 25 cc. physiological saline 

 Ic. 6.0 grams suspended in 40 cc. physiological saline 

 Id. 2.4 grams suspended in 96 cc. distilled water 



