140 PROTEIN POISONS 



the injection of from two to three times the amount which 

 would surely have proved fatal for an untreated control. 

 This would indicate that during the course of the treatment 

 the animal had developed either a slight degree of immunity, 

 or had established a certain amount of tolerance for the 

 poison. Which of these explanations is the correct one 

 can only be determined after a careful study of the subject 

 of the possible production of passive immunity and the 

 demonstration of a possible antibody in the blood of treated 

 animals. At present, owing to the slight amount of increased 

 resistance which the animals exhibit to the action of the 

 poison, we are inclined to believe that the question is one 

 of tolerance. Although the degree or tolerance thus far 

 secured has been limited, we do not feel justified in con- 

 cluding that greater resistance to the poison may not be 

 obtained. There are many factors of primary importance 

 in this work, all of which must be carefully studied before 

 definite conclusions can be drawn. For example, the 

 interval of time which is allowed to elapse between the 

 injections is a matter of first importance. Since the length 

 of time over which the poison acts is apparently so short, 

 it seemed quite probable that any reaction which might 

 occur on the part of the body would develop in a compara- 

 tively short time after the injection. With the object of 

 ascertaining whether this was true or not, animals were 

 treated daily with gradually increasing doses with the 

 following results: 



TABLE IX 



60 MG. OF THIS POISON INVARIABLY CAUSED DEATH IN UNTREATED 

 ANIMALS WITHIN ONE HOUR 



Pig No. 1. Pig No. 2. Pig No. 3. Pig No. 4. Pig No. 5. 



Day. Wt., Dose, Wt., Dose, Wt., Dose, Wt., Dose. Wt., Dose, 

 gm. mg. gm. mg. gin. mg. gm. mg. gm. mg. 



