614 THEORETICAL NUTRITIVE VALUES. 



that the different kinds of fodder vary very much in quality, or that those 

 who determined their relative values by experiment must have tried 

 their effects upon very different kinds of sto(;k, fed probably also for dif- 

 ferent purposes. Both of these conclusions are no doubt true. We 

 know that the same kind of produce does vary very much in chemical 

 constitution, but it is not likely that different samples of the same kind of 

 turnip are so unlike each other that 29 lbs. of the one will go as far in 

 feeding the same animal as 80 lbs. of another. These great differences 

 in the table, therefore, seem to show that different kinds or varieties of 

 fodder have been used, or under different circumstances, or results so dis- 

 cordant could scarcely have been obtained. 



A certain value, it is true, attaches to the numbers in the table when 

 those given by the different authors nearly agree. Thus, about 20 of 

 potatoes and 30 of carrots appear to be equal in nutritive value to 10 of 

 hay. It must be confessed, however, that this subject of the experimental 

 value of different kinds of farm produce in feeding stock of the same 

 Tcindfor the same purposes is still almost wholly uninvestigated. "Will 

 none of the skilful stock feeders, of whom so many are now springing 

 up, turn their attention to tliis interesting field of experimental inquiry ? 



2°. Theoretical values. — But the theoretical values of different kinds 

 of food in reference to a particular object, can be determined by analyti- 

 cal investigations made in the laboratory. This has been done in a 

 very able manner by Boussingault, in reference to the value of different 

 Jcinds of fodder in the production of muscle. These values, according tc 

 his analyses, are as follow, 10 of hay being again taken as a standard : — 

 Theoretical quantities of different Mnds of vegetable produce which ivill 

 produce equal effects in the growth of muscle {Boussingault): — 



Hay 10 



Clover hay, cut in flower . . 8 



Lucerne do 8 



Aftermath do 8 



Green clover, in flower ... 34 



Green lucerne 35 



"Wheat straw 52 



Rye straw 61 



Barley sIb^w ...... 52 



Oat straw 55 



Pea straw 6 



Vetch straw 7 



Potato leaves 36 



Carrot leaves 13 



Oak leaves 13 



T^is table possesses much value. 



Potatoes 28 



Old potatoes 41 



Carrots 35 



Turnips 61 



"White cabbage ..... 37 



V'etches 2 



Peas 3 



Indian corn 6 



Wheat 5 



Rye 5 



Barley 6 



Oats 5 



Bran 9 



Oil-cake 2 



It cannot, however, be relied upon 



as a safe guide in all cases by the feeder, because of the differences in 

 the composition of our crops, which arise from the mode of culture an^d 

 the kind of manure employed. It possesses, however, a higher value 

 from this circumstance — that as muscle in most animals for,ras the larger 

 portion of their bulk, the order in which different kinds of vegetable food 

 promote the growth of this part of the body, may in most cases be adopted 

 as the order also of their relative v^ilues in sustaining animals and keep- 

 ing them in ordinary condition. The same remark, however, will not 



