COMMON FROG. 95 
structure and habits of the young animal as it advances 
towards its perfect condition. 
The impregnation of the female Frog is effected in a 
peculiar and very remarkable manner. Whilst in the 
reptilia, as in most of the superior vertebrate animals, as 
well as in many of the lower classes, the application of the 
vivifying fluid to the ova, is rendered certain by actual in- 
sertion within the body previously to their expulsion,—and 
in the fishes, this is effected after their actual depositions, 
—in the Frog it takes place during the passage of the eggs 
from the body of the parent. As the season of spring ad- 
vances, the renewal of active existence after its temporary 
suspension is evinced by the most energetic action of the 
procreative orgasm. The male Frog leaps on the back of 
the female, and grasps her behind the arm-pits with his fore 
legs, for which purpose a temporary development of a 
warty protuberance takes place on the thumbs, by means 
of which his hold is rendered more firm and secure. So 
powerful is this instinct of adhesion, that instances are not 
unfrequent of male Frogs seizing upon and remaining firm- 
ly attached to the surface of large fishes, from which they 
have not been detached without considerable force. Izaak 
Walton quotes a passage from an ancient writer which ap- 
pears to refer to a fact of this kind. ‘“ But before I pro- 
ceed further,” says honest Izaak, “I am to tell you that 
there is a great antipathy betwixt the pike and some 
Frogs; and this may appear to the reader of Dubravius 
(a Bishop in Bohemia), who, in his book of Fish and Fish- 
ponds, relates what, he says, he saw with his own eyes, 
and could not forbear to tell the reader, which was—‘As 
he and the Bishop of Thurgo were walking by a large pond 
in Bohemia, they saw a Frog, when the pike lay very 
sleepily and quiet by the shore side, leap upon his head ; 
