ON VEGETABLE OILS 479 
On Vegetable Oils 
[Extract from a Letter to Sir William Hooker) 
San Carlos del Rio Negro, Venezuela, 
March 19, 1854. 
Vegetables yielding oil abound in this region, but with the 
present scanty population, and their listless lazy habits, it is ex- 
ceedingly difficult to get together even a small quantity of the oils, 
resins, etc., which in Europe would be highly esteemed. Nearly 
all the palm fruits yield oil in greater or less quantity. You are 
aware that very pleasant drinks are prepared here by triturating 
the fruit of the Assai and other palms in water, and adding a small 
quantity of sugar and farinha. The Portuguese give the name of 
vinho to these drinks, though totally different from the palm 
wine prepared in other parts of tropical America (and I believe 
also of Asia). . . . All the palm drinks are exceedingly nutritive, 
and several are slightly purgative, owing no doubt to the oil they 
contain. By allowing the liquid to stand a short time in a basin 
the oil rises to the top, and an idea is obtained of the quantity 
yielded by any particular palm fruit. Of all that I have seen, the 
Caiare {Elceis melanococca^ an actual congener of the African 
palm) yields oil in the greatest quantity and in appearance exactly 
like the oil of E. guineensis^ but I have never heard of its being 
collected and put to any use. The Caiare palm is abundant all 
about the mouths of the Rio Negro and Madeira, but I have not 
seen or heard of it anywhere up the Rio Negro. I sent you a 
spadix with fruit from the Barra do Rio Negro. Why it was called 
" melanococca" is hard to say, for the fruit is of a bright vermilion 
colour. Perhaps Gaertner had only the nut. 
After the Caiare, as to quantity of oil, come the various species 
of CEnocarpus (ffi. Bacaba, patatm^ disticha, etc.). The oil of 
these is apparently of finer quality than that of Caiare ; it is 
colourless and sweet-tasted, and not only excellent for lamps but 
for cookery. The shopkeepers' of Para buy Pataua oil of the 
Indians, and mix it in equal proportions with olive oil, retailing 
the whole as " olive oil," from which indeed even the best judges 
can scarcely distinguish it. I can bear testimony that for frying 
fish, oil of Bacaba is equal to either olive oil or butter. The 
various species of QEnocarpus abound on the Amazon and 
Orinoco, and on their tributaries. I have lately seen the Pataua in 
the greatest plenty throughout the Casiquiari, Alto Orinoco, and 
Cunucunuma. Near the Barra it is frequent, but less so than the 
Bacaba. The forests opposite San Carlos, extending from the Rio 
Negro to the Xie, are literally sown with Pataua. The fruit is in 
season nearly all the year round. We are just now beginning to 
make use of it, and we shall have it (in unlimited quantity if there 
