ORIGIN OF LOWEST ORGANISMS. 59 



boil. After the remainder of the air had been expelled 

 by the ebullition of the fluid, the neck of the flask was 

 hermetically sealed, and the flask itself was subse- 

 quently immersed in the water of the beaker, which 

 was kept for four hours at a temperature between 113 

 and 1 1 S^ F.* The two other flasks similarly pre- 

 pared were kept at a temperature of I i8J-i27j- F. for 

 four hours. In two days, the fluid in the first flask 

 became slightly turbid, whilst in two days more the 

 turbidity was most marked. The fluid in the two 

 other flasks which had been exposed to the tempera- 

 ture of n8J-i27j F. for four hours, remained quite 

 clear and unaltered during the twelve days in which 

 they were kept in the warm bath under observation. 

 These experiments seem to show, therefore, that the 

 prolongation of the period of exposure to four hours, 

 suffices to lower the vital resistance to heat of Bac- 

 teria and Torula, by I4j-i8 F. 



Such experiments would seem to be most im- 

 portant and crucial in their nature. They may be 

 considered to settle the question as to the vital 

 resistance of these particular Bacteria, whilst other 

 evidence points conclusively in the direction that 

 all Bacteria, whencesoever they have been derived, 

 possess essentially similar vital endowments f. Seeing 



* During nearly the whole of the time the temperature was 

 kept at 113 F. It only rose to the higher temperature for about 

 ten minutes. 



f The Bacteria and Vibriones with which Professor Wyman 

 experimented were derived from different sources ; and so far as 



