128 TWENTY-FIRST REPORT. 



aerobieally in the presence of certain molds, e. g., Fusarivm sp. ' (Graham and 

 Brueckner, Jour. Bact. IV, 1919, p. 8), and of certain aerobic bacteria. 



Thus it is being assumed that manure may be one carrier of this organism, 

 and I believe that such an assumption may be justified, as Graham, Brueckner 

 and Pontius found that the feces from chickens liberally fed with B. totulinu^ 

 cultures, when mixed with a wholesome feed and fed to a horse proved fatal, 

 showing that either the toxin passed through their alimentary tract unharmed 

 or that the organisms survived and multiplied in the feces after they were 

 voided, producing toxin characteristically. (Ky. Sta. Bui, 207, 1917, p. 523). 



Again, in my own experiences, spore-forming anaerobes closely resembling 

 the ones fed were recovered from the feces of guinea pigs fed both on pure 

 cultures of B. hotiilinus and of organisms of this type isolated from spoiled 

 peas and chicken soup. If the assumption is correct, that the feces of sus- 

 ceptible or non-susceptible animals, used experimentally or otherwise, may be 

 considered as an important factor in the distribution of this group of toxin- 

 producing organisms, then this may explain why certain foodstuffs, both 

 animal and human, perhaps more especially the former, do become contami- 

 nated with B. iotuliniis, and in their conditions of storage, foster its devel- 

 opment. 



The statement is made in various texts that B. hotuUnus requires a decid- 

 edly alkaline medium for its development and toxin production ; that it will 

 not even grow in an acid medium. These assertions are now known to be 

 incorrect. The experiences of different investigators have proved that under 

 certain commonly occurring instances, this group of anaerobes can and does 

 develop readily and produces an exceedingly potent toxin sometimes in the 

 presence of acid. In the case of poisonous silage, responsible for the death 

 of horses and cattle, these bacteria are found in the surface layer, where 

 enough acid is usually formed to inhibit the growth and consequent toxin 

 production of B. botulinus, if we are to believe the assertions made by various 

 authors. The explanation may be offered that this organism lives in the sur- 

 face silage in association with certain molds which have the power of destroy- 

 ing acid. Graham and Brueckner cite an instance of this (Jour. Bact. IV 1, 

 p. 8). To quote: "In media of an acid reaction (+2.5) in as.sociation with 

 Fusarium sp., favorable growth took place aerobieally. * * * It is prob- 

 able that the soluble toxin is generated even under aerobic conditions in media 

 of an acid reaction in association with Fusarium sp., and other saprophytic 

 bacteria, since mixed cultures of this character proved fatal to giiinea pigs 

 per OS." 



A statement made by Dickson shows, moreover, that an acid reaction is 

 not inimical to B. botulinus. He says, "An acid reaction of as much as 3.2 

 per cent to phenolphthalein does not prevent the formation of the toxin" 

 (Jour. Amer. Med. Assn, LXV, 1915, pp. 492-496). This amount of acid was 

 formed in a can of string beans inoculated with a pure culture of a strain of 



