Biological Characteristics of Bacillus botulinus. 47 



mine-free diets devoid of water-soluble vitamine are used, is 

 averted. The bulky character of such fruits has made it imprac- 

 ticable to feed more than 10 grams per day without decreasing 

 too greatly the intake of other essential nutrients. Ten c.c. of 

 orange juice per day suffice to promote considerable growth. 

 The inner peel of the orange (which Hess has found to be antiscor- 

 butic) seems also to contain some of the other water-soluble vita- 

 mine. It is already evident that the proportions of the latter in 

 the fruits tested is not large in relation to the quantities edible. 



27 (1487) 



Some observations on the biological characteristics of bacillus 



botulinus. 



By Paul F. Orr (by invitation). 



[From the Department of Preventive Medicine and Hygiene, Harvard 

 University Medical School, Boston, Mass.] 



In a study of sixteen strains of Bacillus botulinus, which have 

 been isolated in connection with outbreaks of food and forage 

 poisoning occurring in different parts of the United States during 

 the past five years, a number of interesting facts have been ob- 

 served. While a complete report of the findings will be published 

 elsewhere, it seems justifiable to record at this time some of the 

 salient facts; namely: 



1 . Contrary to the general view that the optimum temperature 

 for growth of B. botulinus is about 22 0 C, we have found that the 

 body temperature 37 0 C, is most favorable for the growth and 

 spore production of all of the sixteen strains of B. botulinus 

 studied. Toxin is readily formed at this temperature. 



2. At autopsy of guinea pigs which have been either fed or 

 injected with cultures of B. botulinus it has been possible to recover 

 this organism quite frequently from the liver and spleen and also 

 occasionally from the heart's blood, the kidneys and the pancreas. 



3. Contrary to the results obtained by previous investigators, 

 guinea pigs, which have been fed or injected with toxin-free spores 

 of B. botulinus, Nevin strain, have died with symptoms resembling 

 those of botulinus poisoning. At autopsy of these animals 

 B. botulinus was recovered from the liver and spleen. 



