Before I followed them I witnessed an incident worthy of note from the standpoint of a naturalist, and of possible importance to us because of the trip we were about to take.  South America, even more than Australia and Africa, and almost as much as India, is a country of poisonous snakes.  As in India, although not to the same degree, these snakes are responsible for a very serious mortality among human beings.  One of the most interesting evidences of the modern advance in Brazil is the establishment near Sao Paulo of an institution especially for the study of these poisonous snakes, so as to secure antidotes to the poison and to develop enemies to the snakes themselves.  We wished to take into the interior with us some bottles of the anti-venom serum, for on such an expedition there is always a certain danger from snakes.  On one of his trips Cherrie had lost a native follower by snake-bite.  The man was bitten while out alone in the forest, and, although he reached camp, the poison was already working in him, so that he could give no intelligible account of what had occurred, and he died in a short time.

Poisonous snakes are of several different families, but the most poisonous ones, those which are dangerous to man, belong to the two great families of the colubrine snakes and the vipers.  Most of the colubrine snakes are entirely harmless, and are the common snakes that we meet everywhere.  But some of them, the cobras for instance, develop into what are on the whole perhaps the most formidable of all snakes.  The only poisonous colubrine snakes in the New World are the ring-snakes, the coral-snakes of the genus elaps, which are found from the extreme southern United States southward to the Argentine.  These coral-snakes are not vicious and have small teeth which cannot penetrate even ordinary clothing.  They are only dangerous if actually trodden on by some one with bare feet or if seized in the hand.  There are harmless snakes very like them in color which are sometimes kept as pets; but it behooves every man who keeps such a pet or who handles such a snake to be very sure as to the genus to which it belongs.

The great bulk of the poisonous snakes of America, including all the really dangerous ones, belong to a division of the widely spread family of vipers which is known as the pit-vipers.  In South America these include two distinct subfamilies or genera—­whether they are called families, subfamilies, or genera would depend, I suppose, largely upon the varying personal views of the individual describer on the subject of herpetological nomenclature.  One genus includes the rattlesnakes, of which the big Brazilian species is as dangerous as those of the southern United States.  But the large majority of the species and individuals of dangerous snakes in tropical America are included in the genus lachecis.  These are active, vicious, aggressive snakes without rattles.  They are exceedingly poisonous.  Some of them grow to a very large