ANIMAL HEAT. DIG FSTION. 



41. The production of this heat, which is called animal heat, 

 seems to depend upon the act of respiration. 



42. The combination of the oxygen of the air with the venous 

 blood, in the interior of the lungs, as we have already seen, causes 

 the formation of a certain quantity of carbonic acid gas, in the 

 same manner as in the case where oxygen combines with carbon, 

 in producing the phenomenon of combustion, and, in both in- 

 stances, must extricate a greater or less quantity of heat. 



43. The faculty of thus producing heat, is common to all ani- 

 mals ; but the greater part of them develope it in so small a degree 

 that it is not appreciable by our ordinary thermometers, while in 

 others, it is so great that we do not require physical instruments 

 to ascertain its existence. 



44. The only warm blooded animals are the mammalia and 

 birds ; all the rest are cold blooded. 



45. The temperature of the body of man, is about 101 degrees 

 of Fahrenheit. It is about the same in the other mammalia, but 

 birds produce more heat, their temperature rising to about 108 

 Fahrenheit. 



LESSON V. 



FUNCTIONS OF NUTRITION Digestion Month 7 he prehension 

 of aliment* Mastication Teeth Their structure The man- 

 ner of their formation Their form and use Saliva Salivary 

 glands Deglutition I'harynr Oesophagus. 



1. The blood, as we have seen, in nourishing all the organs, it 

 maybe said, loses some what of its properties,and requires to retrieve 

 the losses which it thus undergoes ; now, it is renewed by receiv- 

 ing new materials from the productions of the earth. 



2. These materials, destined to the support of the blood, and 

 consequently to the support of the whole body, are furnished by 

 the various aliments or food. 



41. Upon what does the production of animal heat depend? 

 42. How is animal heat produced '( 

 4-'i Is the faculty of producing heat common to all animals ? 



44. What animals are warm blooded? 



45. What is the temperature of the body of man ? What is the tempera- 

 ture of birds? 



1 How does the blood regain those properties which it loses by nourish* 

 .ng tne organs ? 



2. What furnishes the materials for the support of the blood? 



