means of one of the by-products in the economy of the human body 
the use bf which would be far more commendable on account of its 
inexpensive character than for its attractiveness. This fable has 
never been substantiated, and I believe that its origin is simply to 
to be found in the offensive urinal smell developed on the fermen- 
tation of the albuminous matter in crude rubber. 
The methods followed by the native collectors for the coagula- 
tion of the Castilloa latex vary considerably : 
1. -* The latex is washed with water, but just as often this is 
neglected, and then treated with a decoction of the crushed stem 
of the moon-plant, Calonyction speciosum. This, according to Dr. 
MORRIS, is the process practised in British Honduras. 
2. The latex is treated with the juice expressed from Ipomoea 
bona nox which is stated to be highly alkaline. (?) 
3. The latex is collected in shallow holes dug in the ground and 
mixed with a boiling solution of soap in water. This process is 
extensively practised in the Isthmus of Panama. 
5. The latex is treated with a solution of alum. 
These various methods call for the following remarks: — All ol 
them effect the so-called coagulation by adding to the latex sub- 
stances — acids, or alkalies — capable of coagulating the albumen. 
In other words there is no such thing as the coagulation of the 
indiarubher itself. What takes place is that through the addition 
to the latex of either an acid, or faintly alkaline solution the albu- 
men, of which I have shown there is such a large amount in the 
Castilloa latex, is coagulated and carries down with it the rubber 
globules suspended in the latex. If the latex is entirely freed from 
all albuminous matter by a carefully conducted series of washings 
it may still be diluted with water, and then forms a liquid milky 
liquid of a somewhat lighter colour than the original latex, but 
otherwise indistinguishable -from it. But if we now try to coagulate 
this albumin-free liquid with any of the abovenamed coagulants 
we find that the rubber remains quite uneffected, no coagulation 
taking place. Therefore, whenever we coagulate the rubber, we 
can only do so by coagulating it in conjunction with the albumen 
present, and we have at once a product possessing all the irremedi- 
able drawbacks which above we discussed at some length. 
On the plantation at Las Cascadas, Calonyction speciosum is 
very common, and ( ascertained that decoctions prepared from it 
have a strongly acid reaction. Therefore, coagulation with such a 
decoction is simply the wellknown coagulation of solutions of albu- 
men with acids. I have not been able to discover at Las Cascadas 
Ipomoea bona nox. but I very much doubt the highly alkaline 
character of its juice which it is almost certain to possess likewise a 
distinctly acid reaction. The treatment with alum, a process due to 
H. A. Strauss, and purchased from him by the local Government of 
the province of Pernambuco, owes its coagulating action entirely to 
the strongly acid reaction of that salt. This process is a bad one 
from every point of view. The removal of the alum solution from 
the coagulated rubber is physical impossibility, and the pernicious 
action of an alum solution upon the drying rubber is quite sufficient 
