PHYSIOLOGICAL AND BIOLOGICAL RELATIONS 97 



B. Anaphalaxis. 



The toxicity of ricin indicates that there are some protein substances 

 which, when introduced into the animal, cause profound physiological 

 changes resulting ultimately in death. It has recently been discovered 

 that under certain conditions many, if not all, protein substances pro- 

 duce fatal effects when injected into animals, even in small quantities. 

 It has been shown that solutions containing protein, such as blood 

 serum, white of egg, or milk, when injected into an animal, even in 

 large quantities, produce no apparent effect, but if, after ten or twelve 

 days or more, a second injection of a protein solution from the same 

 source is injected, even in very small quantity, the animal quickly 

 dies. The quantity of protein solution required for the first, or sen- 

 sitising, dose in order to produce a fatal effect when followed at a 

 proper interval by the second dose, is excessively small, smaller even 

 than that required by ricin to produce a fatal effect with a single dose. 

 The quantity required for the fatal second dose is somewhat larger, 

 but still astonishingly small. The toxic effect of these protein solutions 

 appears to be specific, since the serum of a horse sensitises the animal to 

 a second dose of horse serum only, for if the second dose is serum of a 

 rabbit, or a cow, or any other animal, no apparent effect is produced. 

 Whether or not this reaction is specific for individual protein substances 

 has not yet been definitely determined, but the scanty evidence now on 

 record indicates that this is probably the case. Little attention has yet 

 been directed to this reaction with vegetable proteins. The only ex- 

 periments thus far recorded being those of Rosenau and Anderson (438), 

 who attempted to use edestin for this purpose but failed, owing to the 

 fact that they used this protein dissolved in strong sodium chloride 

 solution, and those of Wells (567), who tried experiments with gliadin 

 and zein, and found that zein showed this reaction to a high degree, 

 while the preparation of gliadin which he used failed to give similar 

 results. 



C. Hcemagglutination by Seed Proteins. 



Landsteiner and Raubitschek (213) and Mendel (271) have recently 

 shown that the extracts of several seeds when added to a suspension of 

 blood corpuscles rapidly caused them to agglutinate, and also that the 

 agglutinating power of the extracts of various seeds differed greatly 

 and was wholly lacking in some. Whether this effect is to be ascribed 

 to the protein constituents of these extracts remains to be demonstrated, 



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