150 PROTEIN POISONS 



in behavior in the two cases. This is a point on which we 

 are as yet unable to give any definite results. 



In order to study the differences in reaction to the living 

 germ in animals treated with the toxic part and those 

 immunized with the residue it is not only essential that 

 they should receive the same amount of the same culture, 

 but the dose given should not exceed twice that which would 

 prove fatal for a control. When a larger amount of the 

 living culture is given the differences are by no means so 

 clearly defined, although even in this case the animal which 

 has been treated with the residue shows symptoms of 

 severity at a much earlier time. As can be seen from Fig. 

 9, the temperature of a residue pig which had been inocu- 

 lated with twice the fatal dose of a living colon culture had 

 begun to rise at an interval of six hours after injection. 

 However, if an animal which has been rendered immune 

 by treatment with the residue is inoculated with six to 

 eight times the fatal dose of the living culture we find that 

 the temperature curve obtained is somewhat different in 

 character. The temperature falls with the same initial 

 rapidity, but instead of showing an early rise it continues 

 for some time at a low point and it is only at the end of 

 from eight to ten hours that any appreciable rise is mani- 

 fest. This we think is due to the fact that there has not 

 been enough of the bacteriolytic substance directly avail- 

 able to destroy all the bacilli contained in the large 

 amount of culture injected. The remainder of the germs 

 are destroyed by the same factors which are operative in 

 normal animals after the injection of a non-fatal dose of 

 the living bacillus. As can be seen from Fig. 8, it is only 

 after an interval of six to eight hours that there is any 

 appreciable fall in temperature in the case of a normal 

 animal inoculated with a non-fatal dose of the living culture. 

 This, we think, indicates that it is not until this time that 

 any appreciable amount of poison is liberated by bac- 

 teriolysis since, as we have seen in a previous chapter, 

 one of the first signs of the action of the intracellular poison 

 is a fall in body temperature. In a pig which has been 



