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 the fore-end of the 



