318 
NATURAL HISTORY 
proach. In fine weather the notice is always given, but 
not always in rainy weather; this inspires the Indians 
with a dread of travelling among the woods in wet sea- 
sons. In addition to this circumstance, the odour of 
the rattle snake is so extremely foetid, that when it basks 
in the sun, or is irritated, it is often discovered by the 
scent before it is either seen or hear$. Horses and 
cattle frequently discover it by the scent, and escape at 
a distance; but when the serpent happens to be to leeward 
of their course, they sometimes encounter its venom. 
Rattle-snakes are viviparous, producing their young 
generally about twelve in number, in the month of June, 
and by September these acquire the length of twelve 
inches. It has been well attested that they adopt the 
same mode of preserving their young from danger as 
that attributed to the common viper, receiving them 
into the mouth and swallowing them. 
Boa. (PI. 52.) The ground colour of the body of 
this animal, which is the*largest and strongest of the 
serpent race, is yellowish-gray, on which is distributed, 
along the back, a series of large chain-like, reddish 
brown, and sometimes perfectly red variations, with 
other small and more irregular marks and spots. They 
are regularly distinguished from other serpents in the 
under surface of the tail, being covered with undivided 
plates like those on their belly; and their body not being 
terminated by a rattle. There are three species, natives 
of Africa, India, the larger Indian islands, and South 
America, where they chiefly reside in the most retired 
situations in woods and marshy retreats. 
The great boa is frequently from thirty to forty feet 
in length, and of a proportionate thickness. But happily 
for mankind, the rapacity of these creatures is often their 
own destruction: for whenever they seize and swallow 
their prey, they seem like surfeited gluttons, unwieldy, 
stupid, helpless, and sleepy. They at the same time 
seek for some retreat, where they may lurk for several 
days together, and digest^ their meals in safety. The 
smallest effort will then destroy them: they scarcely can 
make any resistance; and, equally unqualified for flight 
