562 



he gives, besides the ordinary word " puissage," the 

 curious Anglo-French name of "stickage." His object 

 is to compare the tendency to tackiness in the different 

 kinds of rubber rather than to di scuss the cause of its 

 occurrence, for which purpose he examined a large 

 series of rubbers in the Musee d'Histoire Naturelle, the 

 Ecole superieure de Pharmacie de Paris, and the Jardin 

 Colonial de Nogent sur Marne. 



Hevea braziliensis, was not tacky, even specimens 

 dating from 1867 were in good condition, and two speci- 

 mens of H. guyanensis were also good. 



The rubber known as Sernamby, from Peru, and 

 Guiyana, chiefly was all tacky, especially where it was in 

 contact with the glass. These Sernambies are stated to 

 be scraps and residues of Hevea but the writer suggests 

 that they are of some other origin. Ceara rubber, out 

 of 8 samples, 3 were not tacky, all the others more or 

 less tacky or resinified. 



Euphorbia Intisy from Madagascar, two out of five 

 were not tacky, the rest spoilt. All the jCastilloa elastica 

 was sticky or resinified. Of Ficus elastica balls of scrap all 

 were tacky. One sample out of five of Ficus prolixa of 

 New Caledonia was not tacky as was a ball of scrap of 

 Ficus albinervis from Reunion. 



Cryptostegia Madagascariensis was all good, Matsdenia 

 verrucosa and Hancornia speciosa were both tacky. Of 

 the Landolphias no less than fourteen species were exa- 

 mined, all of which there were a number of specimens 

 appeared to have a tendency to tackiness but the speci- 

 mens of L. Heudelotu seemed the best. Four species of 

 Mascarenasia were examined and two lisianthiflora 

 and longifolia were neither sticky nor resinous. Fun- 

 tumia elastica, Willughbeia fir ma, Ecdysanthera rosea, 

 Micrechites Napoeensis, Xylinbaria Reynaudii were all 

 tacky, as were Guayule, Lobelia elastica and Vahea sene- 

 galensis. 



In fact the only rubbers which really seemed proof 

 against tackiness wereHevea braziliensis and H. Guyanensis. 



