165 
LE CRITERIUM TECHNOLOGIQUE COMME BASE DES 
METHODES DE SELECTION DES PLANTES CAOUT- 
CHOUCIFERES ET DE PREPARATION DES GOMMES. 
Par M. le Professeur Herm, 
Secrétaire perpétuel de l’Association scientifique internationale 
d’Agronomie coloniale et tropicale. 
[No abstract supplied by the author. ] 
NOUVELLE METHODE D’ANALYSE DU CAOUTCHOUC 
BRUT, ET HTUDES SUR LE MECANISME DE LA CO- 
AGULATION DES LATEX. 
Par M. Marouis, 
Chef de Travaux & la Faculté des Sciences de Paris. 
[No abstract supplied by the author. ] 
[ Discussion. ] 
Mr. P. J. Burcess: Mr. Chairman and Gentlemen—In 
connection with these papers I would like to draw attention to 
a little experiment made some years ago dealing with the 
filtration of latex. Previously to that it was not generally 
recognized that ordinary latex can be filtered and a clear 
serum obtained. I am simply reminding this meeting of the 
fact because I think it might perhaps be a starting point for 
further experimental work, and it appears to me to present an 
avenue which might have prospects, because it would be such 
a simple way of separating the liquid in which the globules are 
suspended without in any way chemically altering the liquid. 
A further interesting fact is that if that liquid be acidified a 
precipitate is formed of some protein matter, which is possibly 
acid albumen. I am simply making the suggestion for the 
benefit of any chemists who are now prosecuting researches on 
this subject. 
The Prestpent: The fact that Mr. Burgess has alluded to 
is well known, but for some reason or other we have not 
succeeded in the last few years in getting much further light 
upon the exact nature of coagulation. As Mr. Burgess is 
aware, the original idea was that the protein contained in the 
serum was really the cause of the coagulation of the rubber, 
but that idea must now be abandoned as a theory, and we have 
I think, to look in another direction altogether for an explana- 
tion of the phenomenon. 
