36 CENTRAL AMERICAN RUBBER TREE. 



however, naked and free, but each is surrounded by a layer of proto- 

 plasm which must contribute a part of the "albuminous constituents" 

 of the latex, if it does not suppry all, though this does not make it 

 easier to understand the recent statement of Dr. C. O. Weber a that 

 such materials are not coagulated by boiling. It might be thought 

 that the boiling coagulates the protoplasm of each globule separately 

 and that the rubber is released afterwards and rises to the top, but 

 Dr. Weber's statements would not bear this interpretation, though the 

 absence of an explanation of the supposed failure of heat to coagulate 

 any of the albuminous matter leaves the impression that this account 

 of the details is not complete. 



SEASONAL INFLUENCES ON LATEX. 



No theoretical consideration need interfere with the recognition of 

 any relation which can be proved to exist between the amount of latex 

 or of rubber obtainable from Castilla and the climatic conditions under 

 which the trees are found. The most direct evidence of such climatic 

 influence is to be found in the seasonal changes in the latex. Such 

 differences in the rubber content of the milk at different seasons has 

 received little attention from recent writers, though it is not a new 

 fact, since a detailed statement was published by Collins over thirty 

 years ago: 



In Nicaragua it is found that although the hule yields the juice at all seasons, the 

 most favorable season is April, when the old leaves begin to fall and the new ones 

 appear. During the rainy season, from May to September, the richness of the juice 

 diminishes. From that time to January the rain diminishes and the milk increases 

 in richness, and the tree prepares to flower. The fruit appears in March, during 

 which month and the succeeding one the milk is at its richest. The yield of caout- 

 chonc contained in an equal quantity of milk would in April be 60 per cent more 

 than in October. & 



The increased richness of the milk in the dry season seems to be 

 recognized in all districts where the dry season is long enough to per- 

 mit the effect to become appreciated, but in localities where the dry 

 weather in which tapping can be done is short there is at once less 

 difference and less opportunity for it to become evident. Where the 

 dry season is long, as at La Zacualpa, the flow of milk becomes small 

 and tapping is deferred until some rain has fallen, when the quantity 

 and qualit}^ of the milk are both at their best. The popular idea is 

 that as the dry season advances the milk becomes too thick to flow, 

 and that during the rain}^ season it becomes too poor in rubber to pay 

 for tapping. The fact that the latex becomes richer during the dry 

 season does not prove, of course, that the additional percentage of 



« Tropical Agriculturist, 22:443, January, 1903. 



& Report on the Caoutchouc of Commerce, 1872, p. 15. 



