THERMAL DEATH-POINT 87 



they cannot be considered to be organisms with 

 which we are at all concerned. 1 



That the statements above mentioned as to the 

 heat-resisting powers of such organisms as have 

 been found within my experimental tubes are such 

 as would generally be admitted may be gathered 

 from the following quotation from a work by 

 Jacques Duclaux, entitled La CTiimie de la Matiere 

 Vivante, published early in 1910, and emanating 

 from one of the workers in the Pasteur Institute. 

 Speaking on this subject, the author says (p. 87) : 



La resistance a la chaleur est, le plus souvent, bien 

 moindre que la resistance au froid : les bacte*ries, dont 

 un assez grand nombre supportent sans aucun dom- 

 mage le temperature de 200, perissent presque 

 toutes dans Peau bouillante, et il n'en est aucune 

 qui supporte une temperature de 20 supe"rieure. 

 Beaucoup plus sensibles, les levures de bieres p6ris- 



1 On this subject see The Evolution of Life, 1907, pp. 85, 282, 

 or The Medico-Chirurgical Transactions, vol. xc., p. 531. I may, 

 however, state here that, according to Christen, they were al- 

 ways killed in 1-5 minutes at 135 C.; while W. P. Park found 

 that 127 C. for two minutes sufficed to destroy them. Then, 

 again, we have nothing to do here with the spores of Monads; 

 but it seems well to mention that, according to Drs. Dallinger 

 and Drysdale (Monthly Miscroscop. JrnL, Aug., 1873), the spor- 

 ules of certain Monads are sometimes capable of surviving a 

 momentary exposure in fluids to 268 F. (131C.) Their 

 trials, however, yielded very contradictory results, and have, I 

 believe, never been confirmed by others. 



