2 66 Journal of Agriculture. [8 May, 1908. 



smelling, poisonous products are formed which are absorbed bv the blood 

 and carried to the liver where they are altered and their toxicity removed. 

 This safe-guarding action is one of the chief functions of the liver and 

 accounts for the very rapid onset of deatli after loss of this organ. 



If there be excess of protein in the food, or if its absorption, be 

 delayed, then toxic bodies are produced in greater quantity than the liver 

 can destroy, and they therefore get into the circulation producing mus- 

 cular weakness, loss of fat, and general decline in health. 



The csecum secretes some ferments, and notably one that can digest 

 and dissolve cellulose and woody fibre. The importance of this ferment 

 does not lie so much in the cellulose becoming fuel-food as in the fact 

 that, in the food that reaches the csecum, much protein, fat and carbo- 

 hydrate has remained unaltered through being enclosed in cells or lying, 

 between tough woody-fibres. In the csecum these bodies are liberated, 

 and their digestion begun. In the non-ruminating animals with small 

 cseca, digestion of cellulose, if it occurs at all, must do so to a very 

 limited extent. We may look on the csecum therefore, as an organ for 

 continuing digestion. It probably has a little absorbing power. In 

 the horse it functions as a water reservoir, serving the same purpose as- 

 the reticulum of the ruminant. When a horse drinks the water is said 

 to pass rapidly through the stomach system, and even through the small 

 intestine to be poured into the csecal cistern. 



DIGESTION IN THE COLON.— The colon varies in a remarkable 

 manner in each six-cies of animal, and little is known of the parts that are 

 analogous in one species as compared with any other. Certain points 

 as regards digestion in the colon may be given as definite — 



1. Digestion continues and is terminated. It is doubtful if the 



succus of the colon has high digestive properties; most of 

 the glands seem to turn out mucus which lubricates the- 

 lining membrane. Bacteria decrease in number in the 

 colon as the rectum is approached. 



2. The colon is the main absorbing portion of the whole alimentary 



tract. This is especially true as regards water, the fluid 

 food-mass changing to semi-solid even solid fseces. Pro- 

 teins are well absorbed, and to a lesser degree the carbo- 

 hydrates and fats. 

 3. The colon is an excretory organ. In starvation, or when the 

 lower part of the colon is disconnected from the rest, it 

 will be found that some fseces are passed. Experiment 

 also shows that many substances, particularly metallic 

 salts, leave the body by this channel. 

 THE F.-ECES. — In the lowest part of the colon the fseces collect, and 

 are moulded into the form characteristic for the animal. When the 

 fsecal mass has reached the rectum, the act of defsecation is excited 

 reflexlv. The fseces consist of the indigestible and partly-digested por- 

 tions of the food together with mucin and excretory products from the 

 colon wall, altered bile pigments, cholestrin, remains of bacteria, and 

 products formed bv these. The character of the fseces depends on the 

 species of the animal as well as the nature of the food, and the rate of 

 peristalsis and absorption. The smell of faeces is due to bacterial pro- 

 ducts chief! v, and is especially offensive when the food contains excess 

 of protein and too little ballast. The colour is partly due to altered 

 bile pigment, and, in the case of vegetable eaters, to the altered chloro- 

 phyll or green colouring-matter of plants. 



