AN INTRODUCTION TO ANIMAL BIOLOGY 25 



skins and who has read the revolting but true accounts of the 

 barbaric cruelty practised by the hunters of the animals 

 which produce these articles of decoration would ever question 

 the painless killing of a few animals for the sake of scientific 

 knowledge which, as we shall see, affects human life in many 

 ways. (6) No one who approves of that relic of barbarism, 

 hunting animals merely for sport and trophies, can conscien- 

 tiously raise opposition to the scientific study of animals. 



Facts such as the above must lead us to take a sensible 

 view of the study of animals. Of course, the dissection* or 

 the taking to pieces of an animal is not as pleasant work as 

 pulling a rose into pieces, but since we want to see for 

 ourselves the most important parts of the machinery in- 

 side an animal, we will be sensible, and set ourselves the 

 task of carefully examining first the outside (external struc- 

 ture) and then the inside (internal structure) of the frog. 



THE STRUCTURE (ANATOMY) OF THE FROG 



" The first step towards an appreciation of animal life must be taken 

 by the student himself, for no booklore can take the place of actual observa- 

 tion. The student must wash the quartz and dig for the diamonds, though a 

 book may help him find these, and thereafter to fashion them into a treasure." 

 From "Study of Animal Life," by Professor J. Arthur Thomson, of the Uni- 

 versity of Aberdeen, Scotland. 



35. External Structure of the Frog. (L) Place a living frog in 

 a plain glass tumbler, and cover with paper or mosquito-netting. 

 The ordinary "jelly-glasses" with tin covers are convenient, if 



* Dissection is the term commonly applied to the work of separating a 

 dead animal or plant into its organs in order to learn the plan of structure. 

 Careless people sometimes confuse dissection with vivisection. The latter 

 term means operating on living animals which have been rendered insensible 

 to pain by means of ether, chloroform, or other anaesthetics. In short, as 

 now practiced by the greatest investigators, vivisection of animals is exactly 

 the same as the surgical operations on human beings. Such operations on 

 animals are occasionally performed with the hope of improving the methods 

 for surgical work. In fact, most of the great operations which surgeons per- 

 form would be unknown had not operations on anaesthetized animals shown 

 the proper methods for operating on the human body. 



