AMERTCAIT FOULBROOD. 



Second Set of Experiments. DiaEASE Material Received from England. 



23 



Temperature. 



Period of 

 heating. 



Results as shown by cultures, October, 1913. 



"C. 

 

 91 

 95 

 96 

 9S 

 99 

 100 

 100 

 100 

 100 

 100 



°F. 

 

 196 

 203 

 205 

 208 

 210 

 212 

 212 

 212 

 212 

 212 



Minutes. 

 10 

 10 

 10 

 10 

 10 

 10 

 1 

 2 

 3 

 4 

 5 



Numerous spores alive (checli). 



Spores not Icilled, about -^ as many as in check. 



All but 2 spores killed. 



All spores killed. 



Do! 



Spores not killed, about \ as many as in check. 

 All but 100 spores killed. 

 All but 20 spores killed. 



Do. 



Do. 



Third Set of Experiments. Disease Material Received from France. 



Temperature. 



Period of 

 heating. 



Results as sho\ra by cultures, October, 1913. 



"C. 

 

 90 

 92 

 93 

 94 

 96 

 98 

 99 



°F. 

 

 194 

 198 

 199 

 201 

 205 

 208 

 210 



Minutes. 

 10 

 10 

 10 

 10 

 10 

 10 

 10 

 10 



Numerous spores alive (check). 



Spores not killed, almost as many as in cheek. 



Spores not killed, about J as many as in check. 



All but 30 spores killed. 



All but 100 spores killed. 



All but 12 spores killed. 



Ail but 1 spore killed. 



All spores killed. 



FotTRTH Set of Experiments. Disease Material Received from 



Cuba. 



Temperature. 



Period of 

 heating. 



Results as shown by cultures, January, 



1915. 



°C. 



"F. 



Minutes. 







92 



198 



10 



Numerous spores not killed. 





93 



199 



10 



Do. 





94 



201 



10 



Fewer spores not killed. 





95 



203 



10 



Do. 





96 



205 



10 



Do. 





97 



207 



10 



Fewer alive than at 96° U. 





98 



208' 



10 



Fewer alive than at 97° C. 





99 



210 



10 



About 12,000 spores not killed. 





100 



212 



10 



About 200 spores not killed. 





100 



212 



11 



Do. 





100 



212 



12 



Do. 





From Table I it will be observed that all the spores taken from the 

 American sample were killed by heating at 96° C. for 10 minutes; 

 that all of those from the English sample were also killed at 96° C. 

 in 10 minutes; that all of those from the French sample were killed 

 at 99° C. in 10 minutes; and that all of those from the Cuban sample 

 were killed at 100° C. in 11 minutes. Spores from the different 

 samples varied, therefore, in their resistance to heating, those from 

 the American and English samples being slightly less resistant than 

 those from the French one which showed in turn slightly less resist- 

 ance than those from the Cuban sample. 



By a comparison of the results it will be observed that many spores 

 among those heated were destroyed at 90° C. in 10 minutes and that 

 the percentage remaining alive when the higher temperatures were 

 used rapidly decreased. The results indicate also that by increasing 

 the temperature the time required to destroy the spores is decreased 

 and vice versa. 



