REPTILIA—FROG. 711 
The female is impregnated neither by the mouth, as some philosophers 
imagine, nor by the excrescence at the thumbs, as was the opinion of Lin- 
nus; but by the inspersion of the male seminal fluid upon the eggs as they 
proceed from the body. 
A single female produces from six to eleven hundred eggs at a time; and. 
in general, she throws them all out together by a single effort; though some- 
times she is an hour in performing this task. It is generally in March that 
she deposits the ova, or spawn. ' 
When the spawn is emitted and impregnated by the male, it drops to the 
hettom. The eggs, which during the four first hours suffer no perceptible 
change, begin then to enlarge and grow lighter; by which means they 
mount to the-surface of the water. The twenty-first day, the egg is seen to 
upen a little on one side, and the beginning of a tail to peep out, which be- 
comes more and more distinct every day. The thirty-ninth day, the little 
animal begins to have motion; it moves at intervals its tail; and it is per- 
ceived that the liquor in which it is circumfused, serves it for nourishment. 
In two days more, some of these little creatures fall to the bottom; while 
ethers remain swimming in the fluid round them, while their vivacity and 
motion is seen to increase. Those which fall to the bottom remain there 
the whole day; but having lengthened themselves a little, for hitherto they 
are doubled up, they mount at intervals to the mucus, which they had quit- 
ted, and are seen to feed upon it with great vivacity. The next day they 
acquire their tadpole form. In three days more, they are perceived to have 
two little fringes, that serve as fins, beneath the head; and these in four 
days after assume a more perfect form. It is then also that they are seen to 
feed very greedily upon the pond-weed. When ninety-two days old, two 
small feet are seen beginning to sprout near the tail; and the head appears 
to be separate from the body. In five days after this, they refuse all vegeta- 
ble food; their mouth appears furnished with teeth; and their hinder legs 
are completely formed. In this state it continues for about six or eight 
hours; and then the tail dropping off by degrees, the animal appears in its 
most perfect form. 
Thus the frog, in less than a day, having changed its figure, is seen to _ 
change its appetites also. As soon as the animal acquires its perfect state 
from having fed upon vegetables it becomes carnivorous, and lives entirely 
upon worms and insects. But, as the water cannot supply these, it is oblig- 
ed to quit its native element, and seek for food upon land, where it lives by 
hunting worms and taking insects by surprise. 
The frog lives for the most part out of the water; but when the cold 
nights begin to set in, it returns to its native element, always choosing stag- 
nant waters, where it can lie without danger, concealed at the bottom. In 
this manner it continues torpid, or with but very little motion, all the win- 
ter; like the rest of the dormant race, it requires no food; and the circula- 
tio is slowly carried on, without any assistance from the air. In the 
