IN HUMBOLDT'S COUNTRY 389 
felt at my having wasted a substance so precious. 
It relieved me, however, from all further im- 
portunity for bureche. 
I retained only one frasco of spirit, into which I 
put two ounces of powdered rhubarb, hoping 
thereby to render it distasteful, as well as to 
increase its medicinal virtues. When my hunter 
— my best man — was taken ill with chills and fever, 
I gave him a strong dose of it, and it set him to 
rights. " That medicine of yours, patron," said he, 
" is bitter, bitter, but it's very, very good." I feared 
he would want it all, but he was put off by my 
assurance that strong medicines could be taken 
only in small quantities, or they became sure 
poisons; and I, of course, repudiated the notion 
that there could be spirit in it. 
On the broad bed of granite, of which a wide 
extent is now dry, I had an opportunity of witness- 
ing the exits of swarms of bats from beneath certain 
large flat slabs which lay upon the rock. Just after 
sunset they issued out in a continuous stream, 
which lasted two or three minutes. From beneath 
a single large stone not less than two or three 
hundred must have issued out. But on the evening 
of the 30th I witnessed the same phenomenon on 
a much grander scale when anchored near the rock 
of Guanari. I had just turned out of my cabin, 
after eating my evening meal, when my ears were 
saluted by a deep roaring sound in the forest in the 
direction of the rock (which, though not more than 
two hundred paces off, was hidden from view by 
intervening trees), quite like that of a coming 
thunderstorm. I ordered the Indians to gather up 
some linen which was drying on the top of the 
