330 THE BEGINNINGS OF LIFE. 



few days to become turbid, then, obviously, the or- 

 ganisms cannot have been killed by this degree of heat ; 

 whilst, if similar fluids, similarly inoculated, which have 

 been raised to temperatures of 140, 149, 158, and 

 i67F, remain sterile, such sterility can only be ex- 

 plained by the supposition that the inoculated organisms 

 had been killed by exposure to these temperatures l . 



Some of these experiments have been repeated several 

 times with the same results. On three occasions, I have 

 found the fluid speedily become turbid which had only 

 been exposed to i3iF for ten minutes, whilst on three 

 other occasions I have found the inoculated fluid remain 

 clear after it had been exposed to a heat of i4OF 

 for ten minutes 2 . 



Wishing to ascertain what difference would be 

 manifested if the inoculated fluids were exposed for a 

 very long time, instead of for ten minutes only, to 

 certain temperatures, I prepared three flasks in the 

 same manner each containing some of the previously 

 boiled solution, which, when cold, had been inoculated 



1 More especially since the fluids which had remained sterile would 

 always, in the course of thirty-six or forty- eight hours after inoculation 

 with living Bacteria, show signs of an increasing turbidity. 



2 That the organisms in question being minute portions of naked living 

 matter should be killed by exposure to the influence of a fluid at these 

 temperatures, will perhaps not seem very improbable to those who have 

 experienced its effects by attempting to keep their fingers for any length 

 of time in water heated to a similar extent. With watch in hand I im- 

 mersed my fingers in one of the experimental beakers containing water 

 at i3iF, and found that in spite of my desires they were hastily with- 

 drawn, after an exposure of less than five-and-twenty seconds. 



