The Diffusibility of Alkaloids Through Rubber. 105 
thus imposed. 1 We have found that various alkaloids and some 
related substances readily diffuse through rubber under such 
conditions. 
Our experiments were conducted as follows: A moderate 
quantity of the pure ether-soluble substance was mixed with 
15-25 c.c. of ether. 2 This mixture was poured through a funnel 
into a new air-tight rubber condom in such a way as to preclude 
the possibility of overflow upon the external surface. The bag 
was then immersed in about 50 c.c. of ether in a narrow salt-mouth 
bottle 7 inches high. With the bag suspended at full extension 
in this position, its mouth was about an inch above the opening 
in the bottle. The protruding condom was supported in the neck 
of the bottle by a tightly fitting cork stopper, which also served 
to keep the bag closed. After a diffusion period of convenient 
length (sometimes 2 to 5 days), 3 the condom was removed from 
the bottle, the ether diffusate was poured into a porcelain dish, 
and the ether completely removed by evaporation on a steam 
bath. At least one appropriate test was then applied to the 
residue. 4 
Meanwhile, the ether solution in the condom was removed. A 
large volume of water was then poured into the suspended bag, 
which, during its distention by the water, was carefully examined for 
signs of leakage. In a few instances defective membranes tempo- 
rarily rendered the outcome doubtful. All results with such bags 
were ignored, of course. Each of the tests, even after reliable posi- 
tive responses, was repeated at least once with a new rubber bag. 
The substances named below (the complete list of those already 
tested in this connection) are readily diffusible under the condi- 
tions of these experiments: 
A. Apomorphin, atropin, brucin, caffein, cocain, codein, 
colchicin, coniin, morphin, narcein, narcotin, nicotin, physostig- 
min, quinin, strychnin, veratrin. 
1 Rosenbloom and Gies, Journal of Biological Chemistry, 1911, ix; Proceedings 
of the American Society of Biological Chemists, p. xiv (December, 1910); also, Pro- 
ceedings of the Society for Experimental Biology and Medicine, 191 i, viii, 
P- 7i. 
2 Substances which did not dissolve readily were triturated with ether in a mortar. 
3 Some of the alkaloids pass through rubber almost immediately under the con- 
ditions of these experiments. 
4 In the experiments with nicotin, the "tobacco odor" of the concentrated liquids 
was very pronounced. 
