96 



Scientific Proceedings (28). 



lactin " by Gay and Southard, who discovered it, is much more 

 potent than that which acts immediately if its power is stated in 

 inverse terms of the amount of blood which must be transferred 

 in order to develop the reactions. One tenth to one cubic cen- 

 timeter will give results after two weeks while fifteen cubic centi- 

 menters are needed to develop the possibility of reaction after 

 twenty four hours. 



In the study of the animals hypersensitive by breeding, these 

 distinctions become greatly emphasized. When the blood of such 

 animals aged four or five weeks, is transferred in quantity (15 c.c.) 

 to fresh guinea pigs they become sensitive to the toxic action of 

 horse serum within twenty four hours. But whether the quantity of 

 blood used be large or small, the anaphylactin or substance sensi- 

 tizing after an incubation period, cannot be demonstrated. 



These experiments were undertaken in the belief that the young 

 born of serum-treated mothers were probably rendered hypersen- 

 sitive by a passive process, analogous, although of opposite result, 

 to the transfer of immunity from mother to offspring. Taken 

 alone or in conjunction only with facts so far developed in regard 

 to this reaction they support this view. Certain experiments not as 

 yet concluded have shown, however, that the sensitiveness of the 

 young animals may last longer than had been supposed. Certain 

 other results, which on control are found to be clearly exceptional, 

 point to the possibility of an influence extending from the treated 

 mother to her grandchildren through the female line. In the hope 

 of extending these observations I defer drawing definite conclusions 

 on these points. 



Some experiments on the reaction of the rabbit to horse serum, 

 incomplete from the point of view with which they were begun, 

 have shown that this animal is much more difficult to sensitize to 

 the point where the intravenous injection of serum will cause 

 sudden death, than is the guinea pig. The toxin-antitoxin mix- 

 ture so effectual for the latter animal does not sensitize the rabbit 

 at all. It would therefore seem most unwise at present to draw 

 conclusions from the recent work on anaphylaxis in animals which 

 would influence in any way the therapeutic use of specific sera. 



