Jan. 8,1917 
Ewes' Milk 
35 
grew older (third and fourth periods) the controlling factor must have 
been the milk. The marked feature of figure 1 is the uniformity in the 
rate of growth between the different groups modified in degree by the 
relative milk yield of the dams. Such results hardly need further com¬ 
ment to emphasize their significance. 
While some of this weight increase represents mast, due to the effect 
of milk fat, yet the limiting factor is the quantitative supply of material 
available for direct structural increase—namely, proteins and ash, the 
latter concerning chiefly lime. 
Aside from the influence of inherited capacity, mast has limitations in 
promoting net increase dependent on rate of growth. Growth, on the 
other hand, is not dependent on mast. Its limitations are set mainly by 
inherited capacity and an abundance of proper food. In other words, 
weight increase from mast can be only relative, whereas growth is not 
limited in the same sense. Recent investigations into the nature of 
growth give added significance to the importance of an abundant supply 
of whole milk during the earlier stages of adolescense. These concern 
not only the specific functions of the various ash constituents (2, 3, 4, 7, 
8, 9) in metabolism but also the newer interpretations of the structural 
differentiation among the various amino-acid derivatives of protein and 
their respective effect on growth (10, 11, 12). Protein under these cir¬ 
cumstances loses its generic value, and its character and source become 
a matter of as great importance as its quantitative sufficiency. 
The function of nutrition is in a sense more complex in the growing 
animal than in the adult, since it involves more metabolic processes. The 
statement may seem somewhat paradoxical, in view of the well-known 
fact that the digestive organs of the young are comparatively rudimentary. 
Nature has overcome this difficulty in providing the proper food in milk. 
Although its virtues have always been recognized on the basis of practical 
results, yet the mere statement of fact that it is perfectly balanced and 
easily assimilated take on added meaning when viewed in the light of 
such results as those of the physiologists cited. 
LITERATURE CITED 
(1) Besana, C. 
1892. Untersuchungen iiber die Schafmilch. In Chem. Ztg., Jahrg. 16, No. 82$ 
p. 1519. 
(2) Forbes, E- B. 
1909. The balance between inorganic acids and bases in animal nutrition. 
Ohio Agr. Exp. Sta. Bui. 207, p.'23-52. 
(3) - 
1909. The mineral elements in animal nutrition. Ohio Agr. Exp. Sta. Bui. 
201, p. 129-172. 
(4) -BEEGEE, F. M., and others. 
19x6. The mineral metabolism of the milch cow. First paper. Ohio Agr. Exp. 
Sta. Bui. 295, p. 323-348. 
