GROWTH OF BACTERIA IN PROTEIN-FREE PRODUCTS 217 



were pure cultures. Wherever a subculture failed to develop, 

 the operation was repeated, heavier inoculations being made. 

 This often changed the result. 



It was found that B. suisepticus was alive on both media after 

 sixteen days, but dead after twenty-four days; B. acne (51) was 

 alive on both at twenty-four days, and on opsine at forty days, 

 the control being contaminated. Streptococcus viridans died on 

 the control before sixteen days, but was still viable on * opsine 

 after two months. After twenty-four days, Leptothrix was dead 

 on the opsine, but living on the control, while at forty days both 

 cultures were dead. B. diphtheriae (strains A, Y.M.S., and 8m), 

 were dead on opsine at two months, forty days and twenty-four 

 days respectively. All were alive on the control medium after 

 two months. 



B. hofmannii could not be subcultured from opsine after forty 

 days, and from the control after two months. All the other 

 forms were still alive on both media at the end of two months 

 (16°). 



Viability tests were also made on 1 per cent decolorized opsine 

 agar, inoculated from the above fourth transplant. No controls 

 were used. 



All of the organisms grew, although in a few instances not quite 

 as well as on the undecolorized opsine agar. After one month 

 at 16° all of the cultures save Leptothrix, B. diphtheriae (strains a, 

 Y.M.S., and 8m.), and Actinomyces were still alive. At the end 

 of one and one-half months, the cultures of B. suisepticus and B. 

 hoffmannii had died. 



Growth, morphology and viability of inenigoccocus, pneumococcus 

 gonococcus and B. influenzas on opsine agar and on fresh 

 beef infusion peptone agar used as control 



The two strains of meningococcus employed grew about as well 

 on opsine (1 per cent) agar as on the control peptone agar, and 

 remained viable equally as long if not longer. Stains from the 

 control cultures showed a great majority of peculiar involution 

 forms of varied types, mostly thread-like filaments or spindle- 



