ROYAL GARDENS, KEW. 
BULLETIN 
OF 
MISCELLANEOUS INFORMATION, 
No. 140.] AUGUST. (1898. 
DCXVL—COAGULATION OF RUBBER-MILK. 
The extensive use of India-rubber in the arts and manufac- 
tures, renders the production of this substance a matter of 
general interest. One of the most kombe problems that awaits 
solution is a simple and effectiv eans for coagulating the 
rabbe aiii and producing an article ` free from impurities and 
capable of being worked with as little preparation as possible. 
In the following paper, which has recently | yr in the 
Annals of Botany Mon xii., pp. 165-171), Mr. R. H. Biffen, B.A., 
Demonstrator in Botany at the University of Cambridge, has 
given an admirable summary of what is alre ady known on the 
subject. Mr. Biffen accompanied Mr. Esme Howard last year on 
a tour through the rubber-yielding countries of T ropical 
America. They visited Mexico, Central America, Brazil, and 
some z the West India Islands. Mr. Biffen has therefore had 
a favourable opportunity for becoming ss borg hoe hs con- 
dititions under which rubber is at present prepared, is 
a position to suggest scientific akoak for the tt proverb 
of the industry. 
While sep de during ins rcs part of 1896 in studying the 
functions of latex, cen on was frequently called to its 
spontaneous dohai on wise’ in contact with the air. 
De Bary describes the phenomenon as follows* :—* As 1 as 
latex comes in contact with the air, and still more quickly on 
treatment with water, alcohol, ether, or acids, coagula appear in 
the hitherto apparently homogeneous clear fluid itself, and inde- 
pendently of the no goce n of the insoluble bodies described by 
Mohl (Bot. Zeit., 1843, No. 33). The stats collect together and 
separate with the senile bodies from the clear fluid. These 
phenomena of coagulation which appear under the action of so 
various agencies point especially to a complicated composition of 
the fluid, and deserve further investigation. 
An examination of the subject was therefore commenced with 
the small quantities of latex obtainable from plants grown for the 
* De Buy; ung. pem Phanerogams and Ferns, p. 184. 
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