124 S. C. PRESCOTT 



plant under actual commercial conditions. In the laboratory 

 tests stringless beans, parsnips, tomatoes and spinach were used. 

 These vegetables were inoculated with cultures of the following 

 organisms: B. coli, B. typhosus, B. paratyphosus A and B, B. 

 enteritidis, B. paracoli, B. subtilis and B. welchii. The vegetables 

 were dried in air in an oven at 80°C. for four hours, after which 

 examinations were made to discover surviving organisms. 



Of the organisms employed, B. subtilis was recovered in typical 

 culture. Organisms resembling B. typhosus and the paratyphoid 

 forms in some respects, but not typical, were found, but these 

 have not yet been tested by serum reactions. All others were 

 destroyed. 



A second series has also recently been studied imperfectly in 

 which B. coli, B. paracoli, B. enteritidis, the paratyphosus A and 

 B strains, Danysz bacillus, B. suipestifer and Microspira protea 

 and B. diphtheriae were used. The treatment given was the 

 same as in the first test, four hours at 80° in an air oven. The 

 only organisms recovered were atypical B. typhosus and atypical 

 B. suipestifer and these have yet to be proved by serum reactions. 



These experiments can only be regarded as preliminary, but 

 so far as they go they are reassuring. It should here be stated 

 that many vegetables contain on their surfaces organisms mark- 

 edly simulating members of the colon typhoid group in gross 

 appearance and in many reactions, as well as microscopically. 

 Serum tests and animal tests may therefore prove the surviving 

 types to be entirely different from the organisms used. 



To make a more satisfactory investigation on this point, I 

 have recently conducted in Chicago a set of experiments under 

 actual working conditions in a dehydrating plant using a method 

 which we had found to be highly satisfactory. The vegetables 

 employed were carrots, cabbage and potato. The organisms 

 used were: B. typhosus, B. paratyphosus A, B. paratyphosus B, 

 B. suipestifer, B. of Danysz (B. murisepticum) , B. enteritidis, B. 

 coli, B. paracoli, B. welchii, B. botulinus, Microspira protea and 

 Micrococcus pyogenes aureus. Heavy inoculations were made 

 from rich broth or agar shake cultures, and the vegetables then 

 submitted to the regular processes of pretreatment and dehydra- 

 tion. 



