240 PROTEIN POISONS 



administered intravenously: (1) With a sensitizing dose 

 of from 0.01 to 0.001 c.c., the second dose was followed 

 uniformly by sudden death. (2) With the sensitizing dose 

 reduced to from 0.0001 to 0.00001, the period of incubation 

 was prolonged, but after this the results of the second 

 dose were the same as in the former instance. (3) When 

 the doses were further reduced to 0.000001 c.c., the animals 

 were not sensitized. Pfeiffer and Mita found that 0.1 

 c.c. of a 10 per cent, suspension of red corpuscles uniformly 

 sensitized guinea-pigs. Vaughan and Wheeler found that 

 1 c.c. of a solution of egg-white in an equal volume of salt 

 solution sensitized all guinea-pigs, and the result was death 

 within thirty minutes or less when the second dose con- 

 sisted of from 2 to 5 c.c. of the same solution. Wells found 

 the minimum sensitizing dose of the purest crystalline 

 egg albumen which he obtained to be 0.05 mg. Kraus 

 and Doerr employed from J to 1 loop of agar cultures of 

 bacteria for the sensitization of guinea-pigs, but Holobut 

 and Delanoe found repeated injections more efficient. 



In guinea-pigs subcutaneous, intraperitoneal, and intra- 

 venous injections of soluble proteins are practically alike 

 in sensitization. Rosenau and Anderson sensitized guinea- 

 pigs by feeding them horse serum. The question of sensi- 

 tization by way of the alimentary canal will be discussed 

 more fully later. 



Rabbits are not so easily and uniformly sensitized as 

 guinea-pigs. Friedemann 1 recommends the following method 

 for the complete sensitization of rabbits: The intravenous 

 injection of 1 c.c. of a heterologous serum per kilo; repetition 

 of the same after one month, and the giving of same dose 

 in the same way eight days later. When this is done the 

 animals are found to be highly anaphylactized. We have 

 found rabbits highly anaphylactized when treated daily 

 with very small intravenous injections for a week, and 

 then after from three to six months later given a like 

 intravenous injection. 



1 Zcitsch. f. Immunitiitsforschung, ii. 



