73 



of avoiding variations in the amount of the underlying fatty tissue 

 included in the sample. It is practically impossible to remove all of 

 the tissue properly belonging with the skin without including a small 

 quantity of the adjacent fatty tissue. 



Average of spinal cord. Table 13 contains the analytical data obtained 

 in regard to the spinal cords of the different animals. Besides the spinal 

 cords proper, these samples included the layer of fatty matter which 

 surrounds the spinal cord in the spinal canal. In some instances the 

 quantity of material was not sufficient to make a determination of 

 the ash, and in three instances the whole of the material was lost. The 

 data show great variations in the composition of the spinal cords of 

 different animals, especially in the content of fat and water. The 

 Berkshire had a spinal cord in which the water predominated, while in 

 Dtiroc Jersey, Xo. 7, the fat was the predominant constituent. The 

 nitrogenous substances are not so large as would be expected in nerve 

 tissue, and those which, are present consist chiefly of the proteids and 

 gelatinoids, the flesh bases being only in relatively small quantity. 



Average of tendons. Table 14 contains the analytical data for the ten- 

 dons of the animals, with the exception of two cases where the samples 

 were lost. Considerably more than half of the tendons in the fresh state 

 is water, while the fat, as is to be expected, is quite low. The nitrog- 

 enous substances, next to the water, constitute the chief material in 

 the tendons, showing the largest percentage of nitrogenous matters of 

 any part of the animal, with the exception of the hoofs. The true 

 proteids and gelatinoids constitute by far the largest portion of the 

 nitrogenous substances, the flesh bases being in relatively smaller pro- 

 portion. The ash in the tendons is higher than in the meats. The 

 summation of the analyses shows uniformly more than 100 per cent, 

 which is probably due to the use of too large a factor in computing 

 the proteids of the different classes from the percentage of nitrogen. 

 Variations in the composition of the tendons are sufficiently well 

 shown in the footings of maxima and minima. The variation in the 

 content of water is not great, while in fat the range is a very consid- 

 erable one, as indicated by the percentages. The agreement in the 

 percentage of nitrogenous substances is quite close, the tendons show- 

 ing very little variation from a mean composition. The ash is also 

 quite constant, the range of variation not being very great, except in 

 the case of the Poland China. 



Average of hoofs. Table 15 contains the analytical data relating to the 

 hoofs of the animals. The fat content of the hoof is extremely small, 

 while water constitutes almost half the entire- weight of this substance. 

 The nitrogenous substances were not separated into three portions, but 

 were all estimated as proteids by multiplying the nitrogen content by 

 the factor 6.25. Considerably more than half of the total weight of the 

 hoofs in the fresh state consists of nitrogenous material. The ash is ifot 

 very high, only in one instance exceeding 1 per cent. The summation 



