128 THE ROYAL SOCIETY OF CANADA 



somewhat according to the medium on which they are suspended, and 

 thus as not all laboratories employ the same method of making broth, 

 should they therefore endeavour to repeat these observations, they might 

 obtain results not wholly consistent with ours. In the course of these 

 observations we found as a matter of fact that the employment of 

 melted peptone broth agar as the medium of suspension did very mater- 

 ially raise the death point of Anthrax spores. With so thin a solution 

 as ordinary peptone broth apparently little change is brought about 

 in this respect. Thus Theobald Smith found no difference in the 

 thermal death point of tubercle bacilli suspended in distilled water 

 and peptone broth respectively, and tubercle bacilli are more suscep- 

 tible organisms than are endospores. As already stated we selected 

 this broth in order that we might thus gain additional controls, and 

 this advantage appeared to us to outweigh any possible disadvantage.^ 



THE CULTURES EMPLOYED. 



Using this apparatus we have tested twenty-six different cultures 

 of sporulating bacteria. Some half-dozen others either died out, or 

 became contaminated during the course of experiments, and as the 

 records are not perfect we have not included them, for the majority 

 we are indebted to Professor Gruner, late Pathologist to the Royal 

 Victoria Hospital, who has made extensive study of the B. subtilis 

 group.^ Unfortunately, Dr. Gruner left Montreal in March, leaving 

 behind no notes as to the species differentiation of many of these foims. 

 Many were merely designated by number. We learn from him that 

 these were members of his collection not necessarily members of the 

 subtilis group, which for one reason or another he was reserving for 

 future study. Time has forbidden that we should make a full study 

 of the differential characters of these forms, while further we have felt 

 some little delicacy in labelling them prematurely. The other portion 

 of our collection we owe to the courtesy of Dr.Winslow who has afforded 

 them from the well-known collection maintained at the American 

 Museum of Natural History, New York. I would here express my 

 very sincere thanks to Dr. Gruner and Dr. Winslow for their courtesy. 



RESULTS. 



For the present we would state the results obtained with bacilli 

 possessing true endospores, leaving for separate consideration the fur- 

 ther discussion regarding the significance of the granules in the tubercle 



^Anthrax spores were killed in an hour at 90°C. when suspended in broth, 

 suspended in agar as noted later, some few rare spores survive this temperature. 



^ Gruner and Fraser: Observations on the B. Mesentericus and allied organisms. 

 Jour. Infect. Dis., Vol. X, 1912, p. 210. 



