THE INFLUENCE OF VARIOUS CHEMICAL AND PHYS- 

 ICAL AGENCIES UPON BACILLUS BOTULINUS 

 AND ITS SPORES 



I. RESISTANCE TO SALT 

 ZAE NORTHRUP WYANT and RUTH NORMINGTON 



From the Bacteriological Laboratory of the Michigan Agricultural College, East 



Lansing, Michigan 



Received for publication April 10, 1919 



A number of statements are made in various text books con- 

 cerning the vitality and longevity of Bacillus botulinus and its 

 spores, as influenced by various chemical and physical agencies. 

 Having a number of different strains of B. botulinus in pure 

 culture, it seemed desirable that these statements should be 

 evaluated in the light of past personal experiences with various 

 strains of this bacillus. A study of the various agencies has 

 been taken up in the order of their importance as nearly as 

 practicable but from the nature of the problems it has been 

 possible to conclude some of the less important phases first. 

 For this reason the studies of the resistance of B. botulinus and 

 its spores to salt are presented at this time. The other data 

 will be published in the order of their completion. 



The statement is made in Kendall's "General Pathological 

 and Intestinal Bacteriology," that pickling in 10 per cent salt 

 solution is destructive to the spores of B. botulinus, killing them 

 within a week, and in Herzog's "Disease-Producing Micro- 

 organisms," 5 or 6 per cent salt is said to prevent the multi- 

 plication of the bacillus. 



Nineteen cultures of B. botulinus were used in the tests. Some 

 of these strains may be identical, as a full history was not sent 

 by some of the laboratories from which they were obtained. 



The medium used was glucose pork gelatin-broth having a 

 reaction of —0.5, and the percentages of salt used were from 



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