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STATE BOARD OF AGRICULTURE. 



7. The Eestraining Influence of Heat Upon the Species 



Isolated. 



This subject has been repeatedly illustrated, yet it may be profitable 

 to append a table illustrating this point. The method was identical 

 with that employed under No. 5 and in fact was a part of it; that is, 

 bouillon tubes were inoculated from cultures, one set was Pasteurized 

 and the other set untouched. From these sets fresh bouillon tubes were 

 inoculated and the time of development was recorded in the following 

 table: 



8. The Restraining Influence of Heat Followed by a Low 

 Temperature Upon the Species Isolated. 



There is little difference between Nos. 7 and 8; yet there may be con- 

 siderable importance attached to the following of Pasteurization by a low 

 degree of temperature. It is asserted that bacteria in the spore form 

 require a higher degree of temperature for development than when in 

 the vegetative form. Of the bacteria isolated, the following table will 

 state whether spores were observed. Plus is affirmative and minus 

 negative. 



No. of micro-organisms:— 



3 6 9 29 30 32 



+ + + + + 



62 107 112 115 116 117 



-++ + + + 



38 43 44 



+ + + 



45 46 48 



+ + 



60 



This table is by no means conclusive, for those in which the spores were 

 not observed may, under conditions not studied, produce spores. Care- 

 ful attention was given to the formation of spores. 



Now we are ready to give our table illustrating the restraining 

 influence of heat followed by a continuous low temperature. Bouillon 

 tubes were used as in previous cases because of the easy recognition of 



