Sensitization to Tubercular Rabbit-Serum. 79 



Each rabbit received five injections of the tuberculosis serum of 

 5 c.c. each. 



The subcutaneous injection of 10 c.c. of the tuberculosis serum 

 into three rabbits, each of which had been previously sensitized by 

 an injection of 1 c.c. of crude tuberculin, caused death in from 24 

 to 50 hours. 



6. This reaction, if found to be sufficiently specific, may be 

 used as another method for the diagnosis of tuberculosis. This 

 test would be made on an animal sensitized with tuberculin, by an 

 injection of the patient's blood-serum. 



7. We have obtained in normal dogs, by the intravenous injec- 

 tion of 4 c.c. of serum from rabbits in the paralytic stage of hydro- 

 phobia (seventh day after subdural inoculation), a marked depres- 

 sion in the arterial blood pressure. A similar reaction was caused 

 by the intravenous injection of a substance (probably cholin), in 

 small doses, obtained from the brains of calves and rabbits. 



8. We made the following experiments, in order to ascertain what 

 relation this reaction (see paragraph 3 above) has to anaphylaxis, as 

 we now know it. Five dogs were employed. Dog No. 1 received 

 a subcutaneous injection of 2 c.c. of normal horse serum. No. 2 

 received 1/75 c.c. No. 3 received 1/100 c.c. No. 4 received 

 1/1,000 c.c. No. 5 received two injections of 1/10,000 with an 

 interval of four days between the injections. None of these dogs 

 gave a reaction which could be recorded on the kymograph, when 

 given intravenously on the following day 10 c.c. of the same 

 normal horse serum. These results apparently indicate that the 

 reaction is simply one of the many phases of sensitization or 

 increased susceptibility, following the action of toxic substances. 

 It resembles then the anaphylactic reaction only to this extent, 

 namely, that although differing from one another, each is simply 

 one of the many phases of increased susceptibility. We have 

 tentatively named the phenomenon observed by us, vasophylaxis. 



We desire to thank Dr. Wm. H. Park, Director of the 

 Research Laboratory, Department of Health, New York City, for 

 his kindness in furnishing us material for these experiments. 



