COMMON FROG. 87 



planation. About the beginning of the eighteenth century, 

 Dr. Gwythers, a physician, and fellow of the University of 

 Dublin, brought over with him a parcel of Frogs from Eng- 

 land to Ireland, in order to propagate the species in that 

 kingdom, and threw them into the ditches of the University 

 park, but they all perished. Whereupon he sent to Eng- 

 land for some bottles of the Frog spawn, which he threw 

 into those ditches, by which means the species of Frogs was 

 propagated in that kingdom. However, their number was so 

 small in the year 1720, that a Frog was nowhere to be seen 

 in Ireland except in the neighbourhood of the University 

 Park ; but within six or seven years after, they spread thirty, 

 forty, or fifty miles over the country, and so at last by de- 

 grees over the whole nation.' What credit may be due to 

 the note I will not take upon me to determine, though it 

 appears perfectly circumstantial, and given upon the editor's 

 personal knowledge ; but Swift's own notice proves indisput- 

 ably the fact of the introduction, and the period about which 

 it took place." 



The respiration in this animal is, as has already been 

 stated, both pulmonary and cutaneous. The former func- 

 tion, that of breathing by lungs, is effected not by successive 

 alternations of contraction and dilatation of the chest, a 

 movement which, as the Frog possesses no ribs, is impossi- 

 ble, but by the act of swallowing air, as in the case of the 

 Testudinata before described. The mechanism by which 

 this act is performed is precisely the same in both cases ; the 

 air is inhaled through the nostrils by the dilatation of the 

 pharynx, the oesophagus being closed to prevent its passing 

 into the stomach ; then the posterior openings of the nos- 

 trils being also closed by the application of the tongue, the 

 pharynx is contracted, and the air forced into the lungs. 

 These organs are of considerable size, lying on each side of 

 the anterior part of the vertebral column ; they consist of 



