44 VOELCKER on the Chemistry of Food. 



tain a large amount of nitrogenized matters. Chemically con- 

 sidered, they ought therefore to possess considerable feeding pro- 

 perties ; but experience has shown that their value as articles of 

 food does not range very high. Mangold- wurtzel leaves, more- 

 over, are very apt to scour animals, and ought therefore to be 

 given to them only in moderate quantities. 



Mangold leaves and turnip tops thus present us with instances 

 which illustrate that the actual value of an article of food cannot 

 always be determined by the same analytical process which in 

 many cases affords good indications of the value of food. Man- 

 gold leaves and turnip tops, it will be seen by a glance 

 at the above tabulated analytical results, contain a very large 

 proportion of inorganic matters, or ash. This ash chiefly consists 

 of alkaline phosphates, which are known to produce a relaxation 

 of the bowels when taken internally, even in moderate quantities. 

 The presence of much phosphate of potash and soda in the leaves 

 of mangolds or turnip tops may thus be the reason why the nutri- 

 tive substances which they contain are not assimilated by the 

 animal organism, and why cattle do not get on well upon such 

 food. 



9. HAY AND STRAW (Clover-Hay and Hay of Artificial 

 Grasses). The composition of clover-hay, and the hay of arti- 

 ficial grasses, necessarily is regulated by that of the fresh plants 

 which are grown for hay, and which we have seen differ often 

 considerably in composition. Moreover, the composition of hay, 

 and with it its nutritive qualities, depend very much upon the 

 time at which the plants are cut down, on the state of the weather 

 at haymaking time, and the care bestowed upon the haymaking 

 process. For these reasons, it is not practicable to attach a 

 precise nutritive value to clover-hay. 



Composition of Clover-hay and Hay of Artificial Grasses. 

 (According to Professor Way's data.) 



