Animal Nutrition. 61 



concerned, especially the work of digesting feed. A bulky- 

 fodder requires more energy on tlie part of the animal to move 

 it through the digestive canal, and larger quantities of digestive 

 fluids to extract its nutritive elements than does a concentrated 

 todder; hence the importance of supplying hard-worked horses, 

 mil ell cows and fattening animals a concentrated, easily- digested 

 ration. 



88. Concerning the fattening process. — The process of fatten- 

 ing depends on the amount of nutrients taken up by the system 

 over and above its requirements. It is therefore evident that 

 anything which will decrease the oxidation processes going on in 

 the body, that is, decrease the waste caused by the wear and tear 

 of muscles and internal organs, will prove conducive to fat pro- 

 duction. The quantity of oxygen taken up by the blood is 

 dependent on the nutritive condition of the body; the more 

 material supplied and the more energetic the processes of decom- 

 position, the more oxygen is needed. There is, however, a limit 

 to the amount of oxygen that can be absorbed by the blood, this 

 limit being determined by the amount of blood in the body and 

 its content of haemoglobin, the characteristic coloring matter of 

 the red blood corpuscles. A small amount of blood and a small 

 hsBmoglobin content of the same are therefore favorable to fatten- 

 ing. We see in this a possible explanation of the custom reported 

 to be practiced in some parts of Europe of bleeding fattening 

 animals. 



Reference has been made to the possible formation of fat by a 

 degenerative process from the muscles of the body through phos- 

 phorus poisoning; (78) the phosphorus in this case acts as a 

 poison by depriving the blood of its oxygen, and the result is the 

 formation of fatty matter from the muscular tissues. 



89. Influence of light on fattening. — The influence of light on 

 fattening has been studied by Graffenberger, ^ the experiments 

 being made with both young and full-grown rabbits. One set of 

 animals was kept in the light, and another in a dark room. The 

 investigator found that the content of haemoglobin in the blood 

 of the rabbits kept in the dark was decreased, and the amount of 



* Pfluger's Archiv, 53 (1893), p. 288. 



