54 THE BIOLOGY OF THE FROG chap. 



ing the early part of the summer it is busily engaged in the 

 attempt to satisfy its hunger. In midsummer, when the 

 body has compensated for its losses, the frog often betakes 

 itself to a place of concealment, coming out only at intervals 

 to obtain food. This period of comparative inactivity has 

 been spoken of as a summer sleep, but according to Fischer- 

 Sigwart a true summer sleep does not occur either in frogs 

 or toads. There is only a period of comparative rest after 

 the need for a large amount of food has ceased. 



In summer, the frog has food in abundance, and it is. less 

 liable to fall a prey to enemies than during the breeding 

 period. It can bask in the sun, seek the shade when it is 

 too warm, or plunge into the water to moisten its skin or 

 cool its body. It is usually on its guard, however, against 

 whatever enemies may prey upon it, but from most of these 

 it frequently has near at hand a ready means of escape. It 

 is free to enjoy life as best an amphibian can, and to store 

 up food for passing the winter and for the ripening of the 

 sexual products for the following spring. To keep alive its 

 stock, a process which incidentally implies the preservation 

 of its own body, is the great end of the frog's existence. 



Injuries ; Power of Regeneration. — As the frog is preyed 

 upon by several enemies, specimens are often found in which 

 fingers or toes, or sometimes the entire hand or foot, are 

 missing. In most cases they are doubtless individuals which 

 have had these parts bitten off and were fortunate that only 

 a portion of their body was left in the possession of the 

 enemy. Even severe wounds in the frog heal very readily. 

 Fischer-Sigwart has observed that if a frog is wounded it 

 betakes itself to the water, and if an individual keeps in the 

 water during the summer, one may be pretty sure that it has 

 received some injury. 



The power of regeneration possessed by some of the 



