XX11 CONTENTS. 



These products identical with the constituents of blood ... 47 



The blood of animals is therefore formed by vegetables ... 48 



Uses of the non-azotised ingredients of food 50 



Changes of the food in the organism of carnivora 53 



Carbon accumulates in the bile 58 



Nitrogen in the urine 59 



The carbon is consumed or burned 60 



True function of the bile 62 



Amount of bile secreted ... ... ... ... ... 64 



Assimilation more energetic in the young animal 67 



The butter, sugar, &c., of its food support respiration ... 68 



The same is true of the class of herbivora 70 



Waste of matter very rapid in carnivora 76 



Importance of agriculture to population 77 



Assimilation less energetic in the carnivora ... ... 80 



Origin of fat in domesticated animals ... ... ... 81 



Its formation is a source of oxygen ... ... ... ... 86 



It is formed when oxygen is deficient, and is a source of 



animal heat 88 



Elements of nutrition and of respiration ... ... ... 96 



Gelatine incapable of serving for nutrition, strictly so called 97 



But it may serve to nourish the gelatinous tissues ... ... 98 



PART II. 



THE METAMORPHOSIS OF TISSUES. 



Discovery of proteine ... ... ... ... ... 1 05 



It is formed by vegetables alone 106 



Theory of chymification 108 



Use of the saliva 113 



Source of the nitrogen exhaled from the lungs and skin ... 114 



Composition of proteine 121 



Composition of the animal tissues ... ... ... ... 1 25 



Gelatine contains no proteine, although formed from it ... 128 



The secretions contain all the elements of the blood .. 132 



