EUrHORBIACJiJL. 169 



of the trees wliicii produce them are cultivated on this account, 

 l^rincipally species of Hevea in Guiana and the northern provinces of 

 Brazil. All the caoutchoucs of Eupliorhiaceœ proceeding from these 

 countries were formerly attributed to H. guianensis^^ or Siphonia 

 elastica; but we now know that the same substance is extracted at 

 Para from other species of the same genus, such as //. lutea,~ 

 hrasiliensis,^ ternata^^ rigidifoUa^'' paucijlora^^ Bentlmmiana^ and 

 SpruceanaJ' The latex flows û'om incisions made in the tree," 

 out of the rainy season, because then the juice is poor in useful 

 materials. A horizontal gash is first made with a knife or hatchet 

 in the trunk, some inches from the base ; after which another is 

 made, vertical and elongated, the bottom of which joins the first, 

 and then receives shorter incisions on the right and left, oblique and 

 descending, disposed parallel to each other like the feathers of a 

 quill. The juice which flows from these cuts is received below in 

 shells or earthen bowls. The trunk is sometimes compressed, to 

 hasten the flowing, with ropes of bind-weed surrounding it crosswise. 

 The latex, at first white and opaque like cream, slowly thickens, the 

 deposit of caoutchouc is accelerated by the action of gentle warmth 

 on small quantities placed in vessels of clay or even of wood. The 

 elevation of temperature is obtained by the combustion of the fruit 

 of the palm, placed in a brazier or in vessels with large necks, pro- 

 ducing much smoke, which thickens, dries, and at the same time 

 cotours the product. A more modern process consists in precipi- 

 tating the caoutchouc, by a solution of alum, which is then submitted 

 to the action of a strong press. 



The existence, in a lai'ge number of Eupliorhiaceœ^ of astringent 



1 AoBL. Ouiaii. 871, t. 335 {S. peruviana). — rar. 237. — IBcrea paracusis R. Br. MSS. (ex H. 



M. Arg. Prodr. 719. — Jatroplui elastica L. Suppl. Bn. in Atiansonia, iv. 284). — B. discolor M. Aro. 



422. — Siphoma elaitica VVRS. .%». ii. 688 — .A. Prodr. n. 2.— SipJionia discolor Bestji. in Hunk. 



JuBS. Euphorbiac. t. 12. — Kl. in Sayn. Arzn. Jonrn. (1354), 369.— S. brasilieiisis Benth. loc. 



xiv. t. i.—S. Cahuclm W. Spec. iv. 567.-5. cit. (nee K.). 



guianeiisis J. ex H. Bn. Euphorb. 326, t. 1.5, fig. ' M. Arg. Prodr. 718, n. i.—Siphonin rigidi- 



1-11. [Bnls de seringue, Pao seringa.) folia Spruce, ex Benth. loc. cit. 



2 Spruce, MSS. ex Benth. in Muuk. Jour. 6 jj_ ^jj^g. Prodr. n. 3. — Siphonia paucijlora 

 (1854), 370.— M. Akg. Prodr. 719, n. 7.— H. Bevth. loc. cit. 



Bn. in Adansonia, iv. 285. — 5. apiculata H. Bn. 7 M. Arg. Zinnœa, xxxiv. 204. 



lgg_ i-n^ 8 Caoutchouc is also extracted, it is said, fi-om 



' M. Aro. in Linnœa, xxxiv. 20i.— Siphonia several species of Micrandia from Para (see H. 



irasiliensis H. B. K. Nov. Gen. et. Spec. vii. 171. Bn. in Adansonia,i\. 286). 



—Kl. in ifay». ^)-s». C?e«i. xiv. t. 5. ' CoLLiNS.iJf/). o« M<! C«o»('f/,. o/ComM. Lond 



< Micrandra tertiata R. Br. in Benn. PI. Jav. (1872), 8, 36. 



VOL. V, 



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