322 



THE REASON WHY : 



" Onely these marishes and myrie bogs, 



In which the fearefull ewftes do build their bowres, 

 Yield me an hostry 'mongst the croaking froys." SPENSHR. 



1027. Why when the frog is breathing does it keep its 

 mouth firmly shut, and also continually raising and lowering 

 the skin between the bones of the under jaw ? 



Because, owing to its peculiar 

 structure, it cannot breathe with 

 the mouth open ; and if it 

 were forcibly kept open, the 

 animal Would die of suffo- 

 cation. 



1028. The explanation of this ap- 

 parent anomaly is as follows : The 

 frog receives the air which is to be 

 conveyed to the lungs through the 

 nostrils, but there is no vacuum or 

 cavity formed by the expansion of 

 the thorax, so that the mere pressure 

 of the atmosphere following the expansion, does not, in this instance, 

 innate the lungs. An effort is required after the air is taken ii,to the 

 body, and that is performed chiefly by the tongue. The depression of the skin ol 

 the lower jaw lasts much longer than the elevation, because there is a double 

 operation to be performed the expulsion of the air already in the lungs, 

 and the re-admission of fresh air into the body. When that skin first descends, 

 there is a contractile action of the abdomen, by which the air in the lungs is 

 driven out ; and when that is all expired, the abdomen returns to its natural state ; 

 but being without bones it cannot form a vacuum, and thus the lungs could not be 

 inflated but by some other action capable of overcoming the resistance of 

 their cells. 



1029. How are the showers of frogs, which are often reported 

 as taking place, accounted for ? 



The explanation of this apparent phenomenon is as follows : It 

 is generally about the month of August, and often after a season 

 of drought, that these hordes of frogs make their appearance ; the 

 animals have been hatched, and quitted their tadpole state, and 

 native pond. Finding the fields hot and parched, they seek the 

 coolest and dampest places, and conceal themselves undei 



