298 



L. D. BTJSHNELL 



after heating at 80°C. for twenty minutes to kill the vegetative 

 forms. The results are shown in table 10. 



TABLE 10 



Influence of organic acids upon the thermal death point of B. subtilis and B. 



mesentericus spores 



TIME 

 OF HEATING 



FEB CENT OF N/1 ACID ADDED TO BROTH 



0.5 per cent 1 per cent 2 per cent 4 per cent 



B. subtilis added 7, 305, 000 per cubic centimeter 



B. mesentericus added 2,500,000 per cubic centimeter 



B. subtilis added 17,500,000 per cubic centimeter 



Tartaric 



15 

 30 

 60 



520, 000 



73,000 



600 



410, 000 



54,000 



576 



52,000 

 3 

 2 



2,000 

 3 

 



B. mesentericus added 2,145,000 per cubic centimeter 



B. subtilis added 27,000,000 per cubic centimeter 



The results show that there is very Uttle difference in the action 

 of these organic acids. The acetic is perhaps a little more effec- 



