MICHIGAN ACADEMY OF SCIENCE. 129 



B. hotulinus of low virulence. The majority of the cans of string beans in this 

 same series varied from 2 to 2.5 per cent normal acid. Dickson cites another 

 case where death followed the eating of canned pears and of canned apricots, 

 the latter being a decidedly acid fruit. (Ibid. LXIX, 1917, p. 966-968). 



In my own experience, February 9, 1918, a series of cans of common vege- 

 tables and acid fruits was inoculated with a pure culture of a strain of low 

 virulence for exhibit purposes. The can of cherries (a pint Mason jar) a 

 month later showed a bulged top, and over a year later, March 17, 1919, the 

 can was open aseptically, giving every evidence of a swell. Microscopic exami- 

 nation of the juice showed no yeasts, only occasional bacteria with spores 

 nearly terminal, and many free spores. This juice contained 17 per cent normal 

 acid. Cultures were made at the same time to see if B. botulinus had sui- 

 vived this excessively long sojourn in a highly acid medium. Also some of this 

 juice (0.25 c. c.) was fed to a guinea pig. No growth, and no ill effects 

 resulted. 



These results of different investigators, even though few in number, seem 

 to suggest strongly that anaerobes of this group can and do grow in highly 

 acid media and produce toxin under certain circumstances. In agriculture, 

 this phase of their life history will bear extensive investigation in connection 

 with the silage obtained from the strictly anaerobic portions of the silo ; in 

 home economics, in connection with temperatures employed in cooking and 

 canning operations. 



This brings us to the consideration of the resistance of B. botulinus and 

 its spores to various degrees of temperature. Here again text books are at 

 fault in copying from one another the statement that B. botulinus spores are 

 relatively non-resistant to heat. They make the statement that heating one 

 hour at 80 degrees C, or 15 minutes at 85 degrees C, destroys them. In a 

 recent number of the Journal of the American Medical Association (Vol. 72, No. 

 2, January 11, 1919), work done at Leland Stanford Univeri-ity under the Botu- 

 lism Research of the California State Council of Defense, shows quite conclu- 

 sively that the spores of certain strains of B. botulinus will survive the process- 

 ing temperatures of the cold pack canning method when subjected to these 

 temperatures for the period of time prescribed for the various food products ; 

 that blanching in boiling water for five minutes does not materially injure 

 spores of resistant strains of B. botulinus; and what is more pertinent, that 

 a steam pressure of 5, 10 or 15 pounds for 10 minutes will not kill the more 

 resistant spores of this species. 



A noteworthy instance developed under my personal observation. During 

 the fall of 1917 I assisted in canning eight chickens. Pint "seal-fast" jars 

 and new rubbers were used. The chickens were cooked in an open kettle till 

 the meat fell from the bones ; they were then boned and canned. Several cans 

 were filled with almost solid meat, while a number of cans were used for the 

 soup alone. Cooked barley and vermicelli were added to several cans of the 



