42 
Scientific Proceedings (41). 
tuberculin and 2 cc of a 1/100 dilution of "P. D. & Co. Adrenalin 
Chloride 1-1000" died within 18 hours. The control, a guinea pig, 
infected with B. tuberculosis, with enlarged glands, was injected 
with 2 cc. of the same diluted adrenalin solution and did not 
show any toxic symptoms and lived. 
B. .5 cc. of the same tuberculin used in the previous experi- 
ments heated from 106 0 C. to no° C. for 1 hour killed a tuber- 
culous guinea pig within 18 hours. 
We have studied the nature of tuberculin poisoning further 
by injecting tuberculin into dogs after one and both adrenals 
have been removed. The characteristic kymograph reaction of 
a tuberculin injection into normal dogs is a quick fall followed 
by an almost equally quick rise in pressure to the previous level. 
The injection of a depressing dose of tuberculin into the dogs 
with the adrenals removed caused a marked drop with a much 
delayed response in the return to the previous pressure level. 
Repeated successive depressing doses, varying from .5 cc to 
5 cc for each dose, of samples of tuberculin injected intravenously 
into several large dogs which had had both adrenals removed did 
not cause a drop to the base line or immediate death, but the 
dogs lived from 2^ to 3 hours after the removal of the adrenals. 
The average life of a dog after both adrenals have been removed 
is about 40 hours. Little or no ether was required after both ad- 
renals had been removed to keep the dogs anesthetized. Clotting, 
which after the intravenous injections of samples of tuberculin 
in several doses, varying from .5 cc. to 5 cc for each dose, had 
always seriously interfered with our work with the kymograph, 
was entirely absent after the adrenals had been removed even 
when tuberculin had been repeatedly injected. 
We have repeatedly injected normal dogs in order to sensitize 
them with 5 cc. of crude tuberculin without apparent injury or 
noticeable toxic effects. 
These results indicate : 
A. That tuberculin is a complex substance consisting of at 
least two poisons, one a blood pressure depressor destroyed by heat 
and antagonized by adrenalin; the other a substance characterized 
by its fatal effects on tuberculous guinea pigs when injected sub- 
