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. 
Precipitation. 

protectiveness. Daboi 
aboia 
Crotalus venom.| Cobra venom. Verioni 

Crotalus I Feebly Moderate None None 
Do. 2 Feebly Copious None None 
Do. e Feebly Slight None None 
Do. 4 Strongly Moderate None None 
Do. 5 Not at all Copious None None 
Do. 6 Strongly Copious None None 
Cobra 7 Not at all None Moderate None 
Daboia 8 Rabbit Not at all None None Slight 

The immune serums 1, 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 o.s5 c.c. of the immune serum and o.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. 

1 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. 
