15 
and at the temperature of boiling water it is soft and excessively 
sticky. The substance a. soluble in carbon bi Err iig nd 
insoluble in alcohol and water 
Ur be re Gamelleira* CEA a similar substance of a chocolate- 
brown colou 
+ We thus see that I mere action of centrifugal force effects the 
Separation of rubber; and from the failure of the processes 
lly loyed, involving the use of chemical reagents, to 
bring teed the clotting of the separated and washed rubb 
rticl must infer that no chemica a occurs in t 
a es, l nge 
ine itself, and that the cause of coagulation must = looked for 
n the medium in which they are susperded. 
From our knowledge of the gren of latex, it is evident 
that the proteids are the most likely substances to cause this 
when riói with acids, alkafioh, excess of M &c., and when 
boiled. 
Unfortunately few latices have as yet been examined for their 
proteid constituents, chiefly on account of the difficulty of obtain- 
ing them in their natural condition in European laboratories, 
d peptone 
in several rubber-yielding latices.t In the clear solatio left after 
separation of the rubber-particles the xanthoproteie reaction 
always showed the presence of proteid pea but under the 
circumstances it was impossible to identify them 
Now albumins are characterized by the iani ion of their 
solution on heating, especially in the presence of dilute acids, 
and globulins by their Pan precipitation with the salt-solution 
and their coagulation on heating. 
Thus = the latex of Hevea brasiliensis is held in the smoke 
of the burning urucuri nuts, the albumin it — is elotted by 
the action of heat in the presence of dilute acetic a 
The globulin of Manihot Glaziovii latex cam on heating 
when the temperature rises to 74—76? C.| 
The acid latex of Castilloa elastica contains an acid albumin, 
which on neutralization forms a gelatinous precipitate. 
n the same way as the white-of-egg p parti in 
seiiston when clotted for the purpose of pgs jellies e ey 
even push the old analogy of blood and latex further, and compare 
the formation of a rubber-clot, y s, to the formation of 
together by fibrin. In this case, — À we must remember 
* Mart. Fl vice E. wd Ficus m: x Mart. Sys. Mat. Med. Bras 
+ This does ot apply to the latex of Mimusops globosa, or E gunt specie, 
which we be be ke t - ogy 8 without t undergoing any c i 
tJ.R 
$ Faraday Fe ice Le "Cuouchouc et la gutta-percha. 
|| J. R. Green, ibid, 
