PRECIPITIN-REACTION WITH SNAKE VENOM 



263 



In the meanwhile, Flexner and Noguchi * were engaged with the study of 

 precipitin formation with different venoms. They made the following 

 statement regarding this particular phenomenon. Precipitins are formed 

 from venom along with or independent of the immunizing principles for 

 venom. There is no relation between the degree of protection afforded by 

 and the amount of precipitin present in the immune serum. Precipitins 

 may arise in treated animals even when the modified venoms are incapable 

 of provoking the production of immunizing substances. Precipitins for 

 different venoms — crotalus, cobra, and daboia — are highly, although not 

 absolutely, specific. Below is a concise statement of their work on the venom 

 precipitins. 



Table 39. 



The immune serums i, 2, 3, 4 were prepared with the venom modi- 

 fied with weak hydrochloric acid; 5 with hydrochloric acid and pepsin; 

 6, 7, 8 with weak .solution of trichloride of iodine. The test was made in test- 

 tubes, each containing 0.5 c.c. of the immune serum and 0.5 c.c. of 0.5 per 

 cent venom solution. 



Ishizaka ^ found that while the pure antivenin of Lachesis flavoviridis 

 produces a copious precipitate with that venom, it produces only a slight 

 precipitate or none at all with the venom of viper. 



' Flexner and Noguchi. Production and properties of anticrotalus venin. Jour, of Med. Research, 



1904, n. s., VI, 363. 

 2 Ishizaka. Studien iiber Habuschlangengift. Zeitschr. f. exper. Path. u. Therapie,' 1907, IV, 88. 



