CHAPTER XI. 

 SOME ACCESSORIES. 



DIGESTION — CIRCULATION, BREATHING, TEMPERATURE — REPAIR 

 OF THE MACHINE CALL-NOTES AND SONG. 



No one who undertook to describe a steam-engine 

 would ever dream of omitting all mention of the 

 furnace. To do so would be to leave out, if not the 

 part of Hamlet, yet a most important part. I have, 

 therefore, determined to write a short chapter on 

 certain " accessories," which would, perhaps, be 

 more correctly called preliminaries. These pre- 

 liminaries are matters of physiology, such as feeding, 

 digestion, breathing, regulation of temperature. 



Digestion. 



A bird is a glorified reptile, and one great difference 

 between him and his cold-blooded ancestors and his 

 cold-blooded surviving relatives also is that he needs 

 far more fuel to keep the flame of his life burning 

 with its normal brightness than they require to 

 maintain their slowly smouldering fires. The bird 

 has a huge appetite, and, except when a demand 

 for a prolonged, uninterrupted effort is made, he 

 craves for ample meals at no long intervals. The 

 boa-constrictor will go a week, or, in captivity, three 

 weeks or more without eating, even during hot 

 weather. But such abstinence does not suit a bird. 



