108 THE DEATH-POINT OF BACTERIA 
each case, when heated to 140° F., turbidity does not 
occur, apparently because there are no living units to 
multiply, and because in these mere thin films of 
fluid dead ferments are as incapable of operating 
upon the organic fluids as they are upon the am- 
monic-tartrate solutions, 
4. Because, in the case of the inoculation of fluids 
which are-not easily amenable to the influence of 
dead ferments, such as a solution containing ammonic 
tartrate and sodic phosphate, this delayed turbidity 
does not occur at all. Such inoculated fluids become 
rapidly turbid when heated to 131° F., though they 
remain clear after a brief exposure to a temperature 
of 140° F. When the living units in the inoculating 
compound are killed, there is nothing left to induce 
turbidity in such solutions. The mere fact that these 
fluids do not undergo change when exposed to the 
air proves conclusively that they are very slightly 
amenable to the influence of the ordinary dead 
organic particles and fragments with which the atmo- 
sphere abounds, The absence of delayed turbidity 
in these fluids serves, therefore, to throw much light 
upon the cause of its occurrence in the organic 
infusions. 
5. And, lastly, I can adduce crucial egdenee sup- 
plied by the ‘Method of Difference, speaking with 
its accustomed clearness. Two portions of the samc 
