its 



LE CRITERIUM TECHNOLOGIQUE COMME BASE DBS 

 M&THODES DE SELECTION DES PLANTES CAOUT- 

 CHOUCIFERES ET DE PREPARATION DES GOMMES. 



Par M. le Professeur HEIM, 



Secretaire perpetuel de I' Association scientifique Internationale 

 d' Agronomic coloniale et tropicale. 



[No abstract supplied by the author.] 



NOUVELLE METHODE D'ANALYSE DU CAOUTCHOUC 

 BRUT, ET ETUDES SUR LE MECANISME DE LA CO- 

 AGULATION DES LATEX. 



Par M. MARQUIS, 



Chef de Travaux a la Faculte des Sciences de Paris. 

 [No abstract supplied by the author.] 



[DISCUSSION.] 



Mr. P. J. BURGESS: 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 PRESIDENT : 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. 



