2 



Scientific Proceedings (30). 



chemical combination) does not modify gelatin in respect to the 

 anaphylaxis reaction. 



Milk does not lose its sensitizing or intoxicating power when 

 heated to 100° for 30 minutes. If large enough doses of serum 

 heated to the same degree are used they will sensitize guinea pigs 

 to unheated serum. Coagulation with alcohol destroys or reduces 

 greatly the toxicity of proteins which it renders insoluble in water 

 (egg albumin) but not proteins that it does not render insoluble 

 (serum albumin). 



Pure zein is actively and specifically toxic to guinea pigs sensi- 

 tized with zein, although it is devoid of tryptophane and lysine. 

 Gliadin, which contains a less quantity of aromatic radicals than 

 almost any other protein except gelatin, has but slight power to 

 intoxicate pigs previously injected with gliadin. 



lodization of different specimens of serum by a constant method 

 did not yield constant results. The partially saturated serum 

 proteins suffered no modification in specificity analogous to that 

 found by Obermayer and Pick in the case of the precipitin re- 

 action. When most nearly saturated they may lose the power of 

 sensitizing for the unaltered serum, but this is uncertain. Pure 

 crystallized egg albumin may be saturated with iodine quite 

 readily, the iodine saturating the unsaturated carbon atoms of the 

 benzene ring. Such iodized albumin retains its specificity un- 

 altered, but seems to lose much of its toxicity for sensitized guinea 

 pigs, nor does it sensitize well to egg albumin. 



Tryptic digestion of serum furnishes further evidence of the 

 protein nature of the substances concerned in the anaphylaxis re- 

 action. Both sensitizing and intoxicating principles are attacked, 

 and slowly decrease in strength as the coagulable protein disap- 

 pears. After 59 days' digestion of a sample of serum so that but 

 4.7 per cent, of the nitrogen was in a coagulable form, the sensi- 

 tizing dose had been changed from one one-thousandth of a cubic 

 centimeter to one fiftieth of a cubic centimeter, while 5 cubic centi- 

 meters intraperitoneally did not intoxicate pigs previously sensi- 

 tized to bovine serum. Digestion of serum does not affect its 

 specificity for species, but the digested serum sensitizes much 

 better to itself than to bovine serum, and conversely. 



