30 



As the result of these aud other experiments, conducted with the 

 greatest accuracy and involving many hundreds of analyses of fodder' 

 and milk, Kuehn concludes that, as soon as the amount of the ration ex- 

 ceeds a certain minimum, an increase is without effect upon the quality, 

 and exercises only a slight influence upon the quantity of the dry sub- 

 stance of the milk produced. 



This principle, tirst enunciated by Kuehn, has been confirmed by an 

 extended series of experiments of similar character made in Hohehen- 

 heim bv Wolff & Fleischer. (Henneberg Journal fiir Landwirthschaft, 

 1871, No. 4.) 



As in the Moeckern experiments the series were divided into periods, 

 in which diflerent rations were led out, the latter varying from 21 pounds 

 of dry substance, contaiuing2.3 pounds of albuminoids, to31 pounds, con- 

 taining 7.4 pounds of albuminoids. These clianges in the fodder were 

 accompanied by corresponding changes in the condition of the animals, 

 as shown by their looks and weight. There was likewise a variation in 

 the quantity of the milk, the difference between the largest and smallest 

 averages being some 7.4 pounds per day. It was also found that the 

 milk given when the animals were in better condition was not only 

 larger in quantity, but was also richer — contained a larger percentage 

 of dry matter, of organic substance. 



The composition of this dry matter, the relative amounts of casein, 

 fat, sugar, and mineral matters, remained unaffected. Indeed, as is 

 shown by, perhaps, thousands of analyses in these and other experi*- 

 ments, the composition of the milk is less affected by the food than by 

 other circumstances, as the time of the " heat" and the advance of time 

 from calving, and particularly by individual and race peculiarities. 



It is worthy of note, however, that Kuehn (Ys.-St., XVI, 1S73, 221) 

 finds that certain foods seem to cause a slight increase of fat in the milk, 

 an effect which Wolff is inclined to attribute rather to the individual 

 Ijeculiarities of the animal. 



These results are quite well accounted for by the view which Voit, the 

 well-known physiologist in Munich, has of late propounded, (Zeitschrift 

 ftir Biologic, vol. v, 186!), p. 79,) and with apparently great justice, as to 

 the mode of formation of milk by the lacteal glands in the udder : " It 

 was formerly the general belief that the system of lacteal glands was 

 simply a filter of large surface which allowed the passage of certain con- 

 stituents of the blood, (those which make up the milk,) and that conse- 

 quently, the quantity and quality of the food may determine the quan- 

 tity and quality of the secretion, (milk,) as is the case of the urine which 

 is filtered from the blood by the kidneys." He says that this is not the 

 case, however, but that the milk, instead of being filtered out of the blood 

 by the lacteal glands, is made of the lacteal glands themselves. " The 

 lacteal glands prepare the fluid in their cells, or rather the milk is the 

 gland dissolved. The milk is not a product of the activity of the glands ; 

 it is the glands changed to a liquid form. * * The milk is essentially 

 this organ liquified by fatty degeneration. * * * An influence of 

 the food upon the milk is to be expected only when the lacteal glands 

 are first affected. These need albuminoid matters for the structure of 

 their cells. The albuminoids of the food are efficient ouly in forming 

 more of these cells in the glands, which in part degenerate into fat, and 

 in part take up fat from the blood." 



In this view it is easy to see that when the cow is well fed and in good 

 condition, there will be plenty of food for the formation of lacteal glands, 

 and hence a plentiful production of milk, and that the composition of 

 these would not be easily affected by variation of the composition of the 



