145 



Composition of Latex. 



Water 



Acetone extract (resin^ ... 

 Protein 



Ash 



Caoutchouc (by difference) 



Four year old. 

 70.00 

 1.22 



10 year old. 



60.00 

 1.65 

 2.03 

 0.70 



35.62 



147 

 0.24 

 27.07 



They then examined the aqueous extracts from the total soUds 

 of these latices in respect of their reducing action on FehHng's- 

 solution and obtained the following results in terms of glucose. 



Before inversion. After inversion. 



These figures are interesting as pointing to the much larger per- 

 centages of Carbohydrates contained in the latex from primary tissue. 

 They are only of relative value and do not show the actual amount. of 

 sugars in the original latices as these are partially destroyed by the 

 evaporation of the latex to dryness. 



The appearance of the latex from the leaf stalks under the 

 microscope is interesting and suggestive. A relatively small number 

 of caoutchouc globules of the ordinary appearance are to be seen with 

 a much larger number of smaller globules about one-third of their 

 size. These small globules are in rapid Brownian movement and are 

 not so well defined as the Caoutchouc globules having apparently a 

 much lower refractive index. 



The latex from the petioles idiffers from that of the bark chiefly 

 in the much higher content of the nitrogenous matter. There is also 

 nearly another 3 per cent, of resins or other matters soluble in acetone.- 



The acetone extracted rubber from the latex of the petioles when 

 allowed to stand for a few months is fairly tough and elastic and 

 resembles rubber from mature trees similarly treated. — Ed. 



A paper on this substance was read lately at the Chemical 

 Society (March 2) by Dr. Pickles, who had isolated it from smoked 

 Para Rubber prepared at Singapore and from fine Hard Para of com- 

 merce. It is one of the sugars of latex and had previously been 

 found in latex collected in Java by De Jong. It does not occur in 

 biscuit and crepe being soluble and washed out in preparation. The 

 smoked rubber referred to was doubtless the rubber prepared from 

 the latex at the Botanic Gardens. Dr. Pickles suggested as a 

 possibility that methylinosite is the precursor of rubber in Hevea 

 Braziliensis and outlined a scheme for the gradual transformation of 

 methylinosite into Para rubber by oxidizing and reducing enzymes 

 assumed to be present in latex (Chemist and Druggist 1911, p. 1 14 

 extrj. 



Latex from 10 year old trees 

 Four years old 

 Leaf stalks 



none 

 trace 

 0.36 



0.34 

 0.79 

 2.25 



METHYL-INOSITE IN RUBBER. 



