VEGETATION IN THE CAVERN. 
2C1 
contracted, retaining only forty feet in height, and that it 
continued stretching to north-east, without deviating from 
its primitive direction, which is parallel to that of the great 
valley of Caripe. 
In this part of the cavern, the rivulet deposits a blackish 
mould, very like the matter which, in the grotto of Muggen- 
dorf, in Franconia, is called “the earth of sacrifice.”* Wo 
could not discover whether this fine and spongy mould fali=i 
through the cracks which communicate with the surface 
of the ground above, or is washed down by the rain-water 
penetrating into the cavern. It was a mixture of silex, 
alumina, and vegetable detritus. We walked in thick mud 
to a spot whore we beheld with astonishment the progress of 
subterranean vegetation. The seeds which the birds carry 
into the grotto to feed their young, spring up wherever they 
fix in the mould which covers the calcareous incrustations. 
Blanched stalks, with some half-formed leaves, had risen to 
the height of two feet. It was impossible to ascertain the 
species of these plants, their form, colour, and aspect having 
been changed by the absence of light. These traces of 
organization amidst darkness forcibly excited the curiosity of 
the natives, who examined them with silent meditation" in- 
spired by a place they seemed to dread. They evidently 
regarded these subterranean plants, pale and deformed, as 
phantoms banished from the face of the earth. To me the 
scene recalled one of the happiest periods of my early youth, 
a long abode in the mines of Freyberg, where I made experi- 
ments on the effects of blanching (etiolement), which are 
very different, according as the air is pure or overcharged 
"with hydrogen or azote. 
The missionaries, with all their authority, could not pre- 
vail on the Indians to penetrate farther into the cavern. As 
the roof became lower the cries of the guacharos were more 
and more shrill. We were obliged to yield to the pusilla- 
nimity of our guides, and trace back our steps. The appear- 
ance of the cavern was however very uniform. We found that 
a bishop of St. Thomas of (luiana had gone farther than our- 
selves. lie had measured nearly 2500 feet from the mouth 
* Opfer-erdc of the cavern of Ilohle Berg (or Hole Mountain,— a 
fountain pierced entirely through) 
