200 MANUAL OF CATTLE-FEEDING. 



According to tlie observations of Subbotin, '^* the chief 

 factor in determining the amount of haemoglobin in the 

 blood seems to be the nature of the food. The blood of 

 a dog, e. ff.j fed on a richly nitrogenous diet, was found to 

 have 13.73 per cent, of haemoglobin, while on a non-nitro- 

 genous diet it sank to 9.52 per cent. lie also found that 

 the blood of herbivorous animals, which generally receive 

 a fodder comparatively poor in nitrogen, contained less 

 hiBmoglobin than that of carnivorous animals, which receive 

 a more nitrogenous food. 



We shall see in Chapter VIII. that an increase of the 

 albuminoids of the food increases the capacity of the body 

 to store up oxygen, and here we get a hint as to the way 

 in which this eifect may be produced. 



One other factor determining the amount of haemoglo- 

 bin seems to be the amount of fat already contained in 

 the body. Subbotin found considerably less in the blood 

 of lean than of fat animals. 



That a decrease of the haemoglobin aids the production 

 of fat is indicated by various facts. 



In some parts of Germany bleeding is resorted to, to in- 

 crease the rapidity of fattening, and it has been found by 

 respiration experiments that this operation, while it in- 

 creases the protein consumption, decreases that of fat, 

 apparently by removing part of the blood corpuscles 

 (haemoglobin), the agents by which oxygen is introduced 

 into the sybtcm. It is also a fact of experience that the 

 body, when deficient in blood, is often inclined to lay on 

 fat. It is well known, too, that hcx^I)ivorous animals are, in 

 general, easier to fatten than carnivorous, and it is more 

 than probable that this is due, in part at least, to the 



* Zeitschr. f. Biologic, VII., 185. 



