THE ICEW MUSEUMS. 
14 7 
crude lac encrusts the bark often to a considerable thickness, 
and when simply removed forms stick lac, when melted and 
purified shellac, grain lac, thread lac, and various other forms 
are produced. Lac is largely used in India for covering the 
well-known painted wood-ware, imparting a lasting gloss, and 
preserving the colours. In this country lac is used chiefly in the 
composition of French polish, and for making sealing wax. 
India rubber or caoutchouc is perhaps, at the present time, 
one of the most important commercial products of the vegetable 
kingdom in consequence of the great and increasing demand all 
over the civilised world for the substance as an insulator for 
telegraph and telephone wires. It might at first be thought that 
this useful product was obtained only from one species of plant 
— which indeed was the case when india rubber was first intro- 
duced to use at the latter part of the last century. The Kew 
Museums, however, show what has been done since then, not 
only in the discovery and development of new sources, but in 
the extension of their geographical range, so that the supplies 
of such a valuable substance may be maintained for the use 
of future generations. Much may be learnt as to the nature of 
india rubber in its raw state, and on the mode of collecting and 
preparing it in the forests of Para, by a glance at one of the 
several cases devoted to products of the natural order Euphor- 
biaceae, for it is to a tree of this order, namely, Hccea Ovasihensis 
that a very large portion and the very best quality of the rubber 
of commerce is obtained. We here see how the tree is tapped 
or gashed with a small hatchet to cause the milk to flow, how it 
is collected in small rough earthenware cups, then poured into 
a large pot made of a gourd, which, when full, is emptied into a 
large basin like a washing basin, from which it is ladled by a 
cocoa-nut shell and poured, while yet in a milky or fluid state, 
over a kind of wooden paddle which is held over a fire, the 
smoke and heat of which causes it to coagulate ; successive 
layers of rubber are thus deposited] until it has become suffi- 
ciently thick, and when hard it is slit along the edge and the 
paddle withdrawn when the rubber is ready for exportation. 
Other plants yielding rubber are Manihot Glaziovii, likewise an 
Euphorbiaceous plant and a close ally to the plant furnish- 
ing tapioca. Ficus elastica, the well-known india rubber plant, 
so much cultivated as a parlour plant, which furnishes the best 
Assam rubber. This belongs to the section or tribe Moreae, of 
the natural order Urticaceae. Another Urticaceous plant, but 
belonging to the tribe Artocarpeae, which produces rubber, is 
Castilloa elastica, a tree of Guatemala, Nicaragua, British 
Honduras, & c., the produce of which is known as Central 
American or West Indian rubber. The remainder of the 
rubber of commerce is furnished by plants belonging to the 
natural order Apocynaceae, Landolpliia flovida on the East and 
West Coasts of Africa, L. Owaricnsis in West and Central 
Africa, and L. Kirkii and L. Petersiana on the East Coast ; while 
