ORIGIN OF LO WEST ORGANISMS. 5 7 



In experimenting upon rather higher organisms, 

 with which there is little difficulty in ascertaining, by 

 microscopical examination, whether they are living or 

 dead, I have found that an exposure even to the lower 

 temperature of 131 F. for five minutes, always suffices 

 to destroy all signs of life in Vibrios, Amoebae, Monads, 

 Chlamydomonads, Euglenae, Desmids, Vorticellae, 

 and all other Ciliated Infusoria which were ob- 

 served, as well as in free Nematoids, Rotifers, and 

 other organisms contained in the fluids which had 

 been heated. 



These results are quite in harmony with the 

 observations and experiments of M. Pouchet and 

 of Professor Wyman, as to the capability of resisting 

 heat displayed by Vibriones and all kinds of ciliated 

 infusoria. According to the former,* the majority 

 of ciliated infusoria are killed at, or even below, the 

 temperature of 122 F., whilst large Vibriones are all 

 killed at a temperature of 131 F.j According to the 

 observations of Professor Wyman, the motions of all 

 ciliated infusoria are stopped at less than 130 F., 

 whilst Vibriones, taken from the most various sources, 

 also seemed to be killed at temperatures between 

 1 30- 1 36-4 F. Similarly, we find Baron Liebig quite 

 recently making the following remarks concerning 

 a species of Torula : " A temperature of 60 C. 



* ' Nouvelles Experiences,' etc., 1864, p. 38. 

 t ' American Journal of Science and Arts,' Oct. 1867. 



