256 STUDIES IN EMMUNITY. 



The specificity of the sensitizer in this instance was as distinct as 



that of the precipitin , and is analogous to the specificity of antimicrobial 

 and hemolytic sensitizers. 



There remains to describe certain experiments that we have 

 made, suggested by the lack of specificity in many of our sera. We 

 have endeavored to determine whether these sera were active only 

 against the particular substances used in immunization and were 

 without effect on other substances from the same animal species. 

 We can simply add a few examples to those described by other 

 authors. Leclainche and Vallee,* Mertens,f Dicudonne,^ Zuelzer § 

 and Schiitze || found that antihuman sera produced by injecting 

 human blood would give precipitates with urine and pleural exudates 

 from human beings; conversely, the injection of exudates and trans- 

 udates gives rise to a serum that precipitates human blood. 



Schutze^j by injecting powdered human muscle, obtained a serum 

 that sensitized human red blood cells. F. Hamburger** has shown 

 that sera that precipitate cow lactoglobulin and lactalbumin will 

 also precipitate bovine blood serum. 



We have considered whether hen-egg white might not be pre- 

 cipitated and sensitized by a serum other than the rabbit > egg 

 serum. In the following experiment we determined the effect 

 of the serum of a rabbit treated with clefibrinated hen blood, and 

 very active against the corpuscles in question, on hen-egg white: 



Tube 1 Hen-egg white 0.2 c.c. 



S. rabbit > hen blood, 56 degrees 0.6 c.c. 



Rabbit alexin 0.1 c.c. 



Tube 2 Hen-egg white 0.2 c.c. 



S. rabbit > egg, 56 degrees 0.6 c.c. 



Rabbit alexin 0.1 c.c. 



Tube 3 Hen-egg white 0.2 c.c. 



S. normal rabbit, 56 degrees 0.6 c.c. 



Rabbit alexin 0.1 c.c. 



After 5 hours contact, one-thirtieth of a cubic centimeter of 

 sensitized hen blood was added to each tube. 



* Leclainche and Vallee, La Semaine medicale, 1901, No. 4. 



t Mertens, Deutsche med. Woch., 1901, No. 1. 



X Dieudonne, Munch med. Woch., 1901, No. 4. 



§ Zuelzer, Deutsche med. Woch., 1901, p. 219. 



II Schutze, Zeit. fur Hyg., XXXVI, 1901, 459. 



T Schutze, Deutsche med. Woch., XXXVIII, 1901, 487. 



** F. Hamburger, Wiener klin. Woch., 1901, 1202. 



