263 



has confirmed the conclusions of the authors as to its affinity 

 and specific distinction. The genus Bleekrodca has so far been 

 known only from two species, one a native of Borneo (B. insignia, 

 Bl.) and the other of North- West Madagascar (B. madugas- 

 cariensis, BL). It has already been described by Blunie as 

 laticiferous, a character very general in Moraceae, but, so far as we 

 know, there is no evidence of the presence of caoutchouc in the 

 latex of the two species recorded by him. On the other hand, 

 B. tonJcinensis is stated to be very rich in caoutchouc and in this 

 respect reminds us of another Moraceous genus, Casttlloa. 



The occurrence of a rubber-yielding tree in the forests of 

 Tonkin was recorded as early as 1905 in a report by the command- 

 ing officer of the Cercle of That-Khe in the province of Bac-Kan. 

 According to him it was known as ' May-ten-nong,' and attained a 

 height of 10-12 m. with a diameter of 40 cm. The latex was 

 abundant and was collected by the natives, whose attention seems 

 to have been directed to the tree quite recently and accidentally ; 

 in fact they used it only as an admixture to increase the bulk of 

 rubber collected from other sources. Last year, however, 

 Dr. Eberhardt was commissioned to investigate the properties of 

 Uie tree on the spot and the conditions under which it grows. 

 The following is the essence of his report. 



The tree occurs practically all over the province of Bac-Kan 

 (north of Hanoi, and half way between this town and the Chinese 

 frontier), and in the adjoining southern parts of the Cercles of 

 Bao-lanc and Cao-bang ; but Dr. Eberhardt is inclined to believe 

 that it will be found throughout the mountainous districts to the 

 north-west of the delta of the Red River and in the Laos country. 

 In the province of Bac-Kan, it prefers hilly ground with a subsoil 

 of calcareous schist and a deep covering of humus, which, 

 however, must be fresh and well aerated and free from stagnant 

 water. Where the soil is charged with clay, the 'teo-non 

 disappears completely, giving way to a vigorous growth of bamboos. 

 It grows gregariously and mav constitute as much as 40 per cent, 

 of the vegetation. It is a rapid growing, much branched tree 

 and attains a height of 1 2 to 15 m. The bark is thin and white, the 

 wood white, soft and useless for joinery and carpentry, the 

 mode of collecting the latex employed by the natives is very 

 crude and wasteful. It consists in tapping the tree near its base 

 by as many cuts as possible so that the normal flow of the latex is 

 soon interrupted, whilst at the same time the tree is rapiaiy 

 exhausted. Moreover, the product becomes in this way muc * 

 contaminated with impurities. The latex is collected in the noiiow 

 Joints of bamboos and carried to the nearest village or to some watei - 

 course where the contents are poured into a pot containing ^vatei 

 ^vhich is then heated to boiling point. Thus treated i , forms into 

 cakes, the impurities nearly always gathering \V a f* X 

 1 We ar e two seasons for collecting the latex one before .and tin 

 other towards the end of the rainy season. The natives hoy e*e , 

 generally confine their efforts to the latter time, **»«• "JX? 

 much more abundant. This is due to the increased activit ot n 

 organism and to the presence of a greiter qnantity of wato rinm 



^ex,so that finally the amount of ™?^T ^SwotSe 

 811 not greater at the end than just befoie the beginning 



