484 GENERAL THERAPEUTIC MEASURES 



Carbohydrates aid directly in the production of fat. Fat in the 

 food may be directly assimilated as such if there is a suiKcient carbohy- 

 drate and proteid ration to protect it from decomposition. The role car- 

 bohydrates play includes: 



1. The formation of tissue indirectly by protecting the proteid 

 elements from combustion with an insufficient nitrogenous diet. 



2. The generation of heat^ energy^ or mechanical work. 



3. The production of fat. 



Carbohydrates cannot be relied upon as sole articles of food. The 

 fat of the body is derived from the decomposition of proteids and carbo- 

 hydrates, and directly from fat contained in the food. Fat lubricates 

 the tissues, and a reasonable accumulation serves as a store of potential 

 energy to be called upon in time of need, when its action is similar to 

 that of carbohydrates. 'The main source of muscular energy, movement, 

 or mechanical work, is thought to reside in the carbohydrates, because 

 with excessive muscular work there is increased evolution of heat, car- 

 bonic dioxide and water, but no material increase in excretion of nitrogen 

 in the urine. In so far as muscular energy and power depend upon a 

 good machine, in so far do the proteids aid the work of the machine by 

 keeping it in good repair and working order. From this point of view 

 the proteids represent the mechanism by which the work is done ; the car- 

 bohydrates the fuel necessary for its performance. It must be kept in 

 mind that this is but a general statement, since muscular work is also 

 done by protein, and may be wholly done by it, as shown by dogs living 

 on lean meat. The exact relative value of carbohydrates and- proteids 

 in the production of the vital forces is still sub judice. 



The classes of food stuffs for the larger animals embrace both green 

 and dry fodder, consisting of the whole plant minus the roots ; parts from 

 which the more valuable portions have been removed, as straw; tubers 

 and roots containing a large percentage of water ; the seeds or grains, con- 

 stituting the most concentrated food; and the seed coverings or chaff. 



Refuse and by-products of manufacture are extensively used, as 

 bran, cottonseed meal, linseed meal, and brewers' grains. In addition, 

 animal matter, as flesh meal, bone meal, and dried blood, are sometimes 

 of value. Pasture grass may be taken as a standard of comparison for 

 green fodders. In 100 lbs. of grass there are approximately digestible: 



Protein .: 1.04 lbs. 



Fat 0.5 lbs. 



Carbohydrates 10.34 lbs. 



Green clover contains considerably more, green rye slightly more, 

 and green oats somewhat less protein; while in green corn fodder there 

 is only about half as much protein. Roots, as compared with green pas- 

 ture grass, possess only one-third the quantity of protein and solids. 

 Potatoes, however, have double the nutritive value of roots. Comparison 

 is made in reference to protein, as that is by far the most valuable nutri- 

 ent, and the amount of carbohydrates and fat do not vary much in 

 similar kinds of fodder. 



Meadow hay, includine such common varieties as timothy and red 



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