106 Tlie Chemical Coiitposltion of Aii'nnnl liodies 



Tabic 11. Coiiijwsitiuii uf Adtiul Bodies. 



Fat calf Half-fat ox Fat ox 



The coiupo.sition o( the lattciiing increa.se (oxen) calculated from tlie 

 data actually recorded by Lawes and Gilbert is as follows: 



Fat 94-54%, Water .j-49 %, Protein O-G %, Ash - ()-«4 %. 



The percentages of water and protein in the increase might be regarded 

 as an indication of growth, but as the animals were four years old it is 

 improbable that any increase in size occurred, or that such increase, if 

 it did occur, would beaccom])anied by a loss of 1-71 lb. of ash ingredients. 

 Further, as the ratio of water to protein in the increase is 9/1 whereas 

 in the whole body it is only 3/1 it is more reasonable to attribute the 

 apparent increase in non-fatty constituents to difference in composition 

 of the two animals. The individual variations revealed by Haecker's 

 data are more than sufficient to justify this assumption. The inference 

 therefore is that, in fully grown animals the fattening increase consists 

 entirely of fat. Tiiis, of course, is acceptable on other grounds, but those 

 who have maintained it have had to do so in the face of numerical data 

 which could lie (|uoted against it and i>f w hich. liitlicrto. lu) satisfactory 

 explanation was fcuthcomiiig. 



It is to be expected that iu other animals I lie compo.siiioii of t lie uou- 

 fatty matter will alter with age iu much the same manner as in cattle, 

 and the author anticipated no difficulty in tracing this relationship in 

 pigs from Swanson's data. A preliminary survey, however, indicated 

 that these results might be affected by the differences in feeding as well 

 as by the age and individuality of the animals, and that the variations 

 due to these combined causes would make it difficult clearly to distin- 

 guish the influence of any one. The best that could be done, it seenu'd, 

 was to divide the data into three groups as shown in the table below. 



It appears that the ratio of protein to ash in pigs is higher than in 

 cattle, but the percentage of water in the non-fatty matter alters with 

 age not only in the same manner but even in the same degree. The latter 



