[shanly] heat resistance OF BACTERIAL SPORES 137 



like conclusion. It must, however, be added that there have been 

 certain contrary observations. Thus in 1888 Yersin^ testing an old 

 glycerine broth culture containing "sporulating bacilli" notes that 

 these withstood being heated for ten minutes at a temperature of 

 60°C., after this exposure they continued to multiply and caused 

 tuberculosis when inoculated into rabbits. We are not told of the 

 effects of heating to the same temperature for twenty minutes. De- 

 Man^ employing the soft, almost cheesy matter, from the udders of 

 tuberculous cows and heating this in sealed tubes found that this 

 would stand an exposure of 60°C. for thirty and forty-five minutes. 

 Two guinea pigs inoculated with material from these exposures be- 

 came tuberculous, while after exposure for sixty minutes the guinea 

 pigs remained well. He repeated and confirmed these results and 

 found also that bacilli in sputum are rendered inocuous by exposure to 

 60°C. for sixty minutes. Here it will be seen that according to his 

 results the time necessary for the destruction of the bacilli is consider- 

 ably lengthened, and more recently Gavina^ according to Wherry, 

 is stated to have found that employing "sporulating" cultures he 

 obtained tuberculosis in guinea pigs when these were inoculated with 

 cultures heated for fifteen minutes at 96 °C., but did not gain any re- 

 sults when he inoculated these animals with "non-spored cultures 

 which had been heated for ten minutes at 80°C., 



It will be seen, that so far as they go, our observations support 

 and confirm those of Theobald Smith and Wherry, and fail to substan- 

 tiate the observations of deMan and Gavina. What is obvious is that 

 these spore-like bodies have no greater resistance to heat than that exhibited 

 by many non-sporing bacteria. 



Our wholly unexpected results with the Gonidia of pencillium 

 and Mucor indicate, however, that typical gonidial spores are possessed 

 of no increased resistance to moist heat. It is thus still within a possibility 

 that these bodies in the tubercle and diphtheroid bacilli are of the 

 nature of gonidia, and as such are to be classed as spores, or if so, as 

 bodies totally distinct in nature from the endospores of bacteria. I 

 regret that I have obtained these results too late in the course of my 

 observations to make a study of the thermal resistance of the gonidia- 

 like bodies in the closely allied streptothrical forms. I would in 

 conclusion suggest that there is need for a full inquiry into the proper- 

 ties of the gonidia of moulds and streptothrices. If, as here indicated, 

 they are not heat resistant, to what extent are they resistant in other 

 ways — to desiccation for example, and to chemicals ? Are we wrong 



1 Annales de T'lnst. de Pasteur, II, 1888, p. 60. 



2 Arch. f. Hygiene XVIII, 1893, p. 133. 



^Ctbl. f. Bakt. Abt. 1, Originale, 70, 1913, p. 115. 



