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 ; 



