4 THE FROG CHAP. 



self. The description of each animal you should follow 

 with the animal before you ; and if you find the account 

 in the book does not agree with what you see, you must 

 conclude, not that there is something wrong with your 

 subject, but either that the description is imperfect or 

 erroneous, or that your observation is at fault and that 

 the matter must be looked into again. In a word, zoology 

 must be learnt by the personal examination of animals : 

 a text-book is merely a guide-post, and all doubtful 

 points must be decided by an appeal to the facts of 

 nature. 



It matters very little what animal we choose as a 

 starting-point a rabbit, a sparrow, or an earthworm 

 one will serve almost as well as another to bring out 

 the essential nature of an animal, how it grows, how it 

 is nourished, how it multiplies. On the whole, one of 

 the best subjects to begin with is a frog : partly because 

 it is easily obtained, partly because its examination 

 presents no difficulties which an intelligent student may 

 not be expected to surmount by due exercise of patience. 



Let us therefore begin our studies by catching a frog 

 and placing it in a convenient position for examination, 

 as, for instance, under an inverted glass bell- jar or even 

 a large tumbler. 



External Characters; Notice, first of all, the short, 

 broad trunk, passing insensibly in front into the flattened 

 head there being no trace of a neck and ending behind 

 without the least vestige of a tail : these constitute the 

 axial parts of the animal. In the ordinary squatting 

 position the back has a bend near the middle, producing 

 a peculiar humped appearance. The head ends in front 

 in a nearly semicircular snout, round the whole edge of 

 which extends the huge slit-like mouth. On the top of 

 fore-end of the snout are the two small nostrils, one on 



