1917] VETERINARY MEDICINE. 581 



of normal serum, as well as with that induced in normal serum by alien 

 substances." 



It is concluded that the so-called " endotoxin " of various pathogenic organ- 

 isms is similar to the toxicity of agar, and that the common conception of 

 endotoxin is fundamentally wrong. "The disturbance in the plasma caused 

 by the introduction of alien substances results in the formation of anaphyla- 

 toxin, the poisonous effects of which have been erroneously attributed to a 

 liberation of the so-called endotoxin." 



VII. Peptone anaphylatoxin, F. G. Novy, P. H. DeKruif, and F. O. Novy 

 (pp. 657-716). — The symptoms and findings in guinea pigs injected with pep- 

 tone were the same as those produced by anaphylatoxin, agar, or by specific 

 anaphylactic shock. A marked exophthalmos was observed and was especially 

 marked in rabbits. Guinea pigs showed the same individual variation to 

 peptone as has been demonstrated for anaphylatoxin and agar. In white rats 

 the injection of peptone resulted in symptoms and findings identical with those 

 caused by anaphylatoxin and agar. The coagulation time of the blood was 

 retarded for an appreciable period. 



It was found necessary to employ very large doses of peptone in rabbits to 

 obtain typical anaphylactic shock and findings. CJonsiderable variation in 

 resistance was observed in rabbits, as in rats and guinea pigs. An immunity 

 or tolerance was shown by the rabbit to repeated injections of peptone similar 

 to that exhibited by the dog or guinea pig. 



" Rat serum on treatment with peptone rapidly yields anaphylatoxin. A 

 peptone suspension is more active than a perfectly clear solution. The fully 

 dissolved peptone does not toxify rat serum as easily, nor does it yield as 

 high a degree of toxicity as do the agar and trypanosome suspensoids. Ex- 

 treme dispersion is, therefore, unfavorable for the reagent." Anaphylatoxin 

 was also produced when guinea pig serum was treated with peptone. 



"A comparison of the effective agar-serum ratio with that of peptone-serum 

 shows that, with regard to rat serum, agar is 500 times more active than pep- 

 tone; with regard to guinea pig serum, it is from 200 to 1,000 times as 

 active. . . . Peptone itself is not toxic, but when brought into contact with a 

 reactive serum or plasma it induces the change which results in anaphylatoxin 

 production." 



VIII. The primary toxicity of normal serum, P. H. DeKruif (pp. 717-775). — 

 " Very rapid transfusion of the blood of normal rabbit to the guinea pig or 

 white rat shows that the toxicity of such blood is subject to great variation. 

 It is often possible to transfuse 10 cc. of heart blood without much effect. 

 Exceptionally, however, the blood from apparently normal rabbits is inher- 

 ently toxic in dose of 2 or even 1 cc, and the plasma and serum from such 

 blood may be correspondingly toxic. The natural resistance of the rabbit 

 enables it to act as a carrier of the poison which may be generated in the normal 

 animal as a result of changed conditions, notably diet. The toxicity of the 

 blood of an apparently normal rabbit may correspond to 100 guinea pig lethal 

 doses per kilogram. A blood which is initially nontoxic becomes poisonous in 

 3 cc. dose, just prior to the appearance of coagulation. The speed of poison 

 production corresponds to that of anaphylatoxin by agar, inulin, trypano- 

 somes, etc." 



The symptoms and autopsy findings in guinea pigs after injection of toxic 

 blood or serum were essentially those produced by anaphylatoxin and in 

 anaphylactic shock. When rat or guinea pig blood or serum was used instead 

 of that of the rabbit identical results were obtained. Homologous blood was 

 found to be distinctly less toxic than heterologous. Large doses of normal 



