372 



NEW ENGLAND FARMER. 



Aug. 



exist in the starch and sngar of the food. Or it 

 may bo water luriii;'J by tlio union of the liydro- 

 gen of the other kinds of food \Yith the oxygen in- 

 haled by the lungs. It is probably derived in part 

 from each of these sources, in proportions which 

 must vary with many circumstances. 



3. But the lungs actually feed the bod}'. The 

 air which enters contains more oxygen than when 

 it returns again from tlie lungs. The oxygen 

 which disappctirs equals in bulk very nearly that 

 of the carbonic acid which is evolved. This oxy- 

 gen enters the lungs, through them into the blood, 

 and with the blood flows on and circulates through 

 the body. It also enters partly into the composi- 

 tion of the tissues, so that it is a real food, and is 

 as necessary to the construction of the human 

 body as tlie other forms of food which are usually 

 introduced into the stomach. The weight of oxy- 

 gen taken up by the lungs exceeds considerably 

 that of all the dry solid food which is introduced 

 into the stomach of a healthy man. 



4. The purposes served by-the oxygon thus in- 

 troduced into the system are very difficult and 

 complicated. But an incidental circumstance 

 which accompanies all its operations in the sys 

 tcm, is the evolution of heat. From the time the 

 solid digestible food enters the blood till it escapes 

 from the lungs, or in the other excretions, it is 

 continually uniting with oxygen into new forms 

 of combination, and at each change heat is pro- 

 duced or given oS. Thus the animal heat is kept 

 up, and thus it is, in a certain sense, correct to 

 say that oxygen is taken in ])y the lungs for the 

 purpose of giving warmth to the body, — or, more 

 poetically, that the body is a lamp fed with oil 

 from the stomach, and with air from the lungs, 

 which burns with a slow and invisible flame, but 

 which ever does burn while iifo lasts, and main- 

 tains a gentle warmth through all its parts. 



THE FOOD MUST REPAIR THE DAILY WASTE OF TUE 

 MUSCULAR PARTS AND TISSUES OF THE BODY. 



Ftom every part of the growing as well as of 

 the full-grown body, a portion is daily abstracted 

 by natural proc.isses, and rejected either through 

 the lungs and skin, or in tlie solid and fluid excre- 

 tions. This pr iportion is so great that in sum- 

 mer the body loses one-fourteenth, and in wintor 

 one-twelfth of its weight daily, when no food is 

 taken. And if food be continuously withheld, 

 the mean duration of life is only fourteen days, 

 and the weight diminishes two-lifths. But the 

 waste or change of material proceeds more rapid- 

 ly when the animal is well fed, so that tlie opin- 

 ion now prcviiils among physiologists that every 

 twenty or thirty days the greater part of the mat- 

 ter of the iiuman body, when adequately fed, is 

 constantly renewed. Tins waste of tlie tissues is 

 more rapid in women than in children, in men 

 than in women, and most of all in men betwe n 

 the age>! of ;50 and 40. The amount of waste is 

 the measure of life. 



The materials for this change must be supplied 

 by tlic food. And the quantities required must 

 be adapted to the nature, age, and sex of the ani- 

 mal. 



The muscles of animals, of which lean beef and 

 mutton are examples, are generally colored by 

 blood; but wiien washed with water for a length 

 of time, they become quite white, and, with the 

 exception of a little fat, are found to consist of a 



white fibrous substance, to which the name of 

 fibrin has been given by chemists. The clot of 

 the blood consists chiefly of the same substance ; 

 while skin, hair, horn, and the organic part of 

 the bones, are composed of varieties of gelatine. 

 This latter substance is familiarly known in the 

 form of fffitc, and though it differs in its sensible 

 propn-ties, it is remarkably similar to fibrin in its 

 elementary composition, as well as to the white of 

 the egg, (albumen,) to the curd of milk, (casein) 

 and to the ^/«i!p?i of flour. They ail contain ni- 

 trogen, and the three latter consist of the four or- 

 ganic elementary bodies very nearly in the follow- 

 ing proi^ortions : 

 Carbon, - - - ... 65 



Hydrogen, - ..... •; 



Nitrogen, - . - . . - ig 



Oxygen, with a little sulphur .ind phosphorus, - 22 



Gelatine or dry glue contains about 2 per cent, 

 more nitrogen. 



The quantity of one or other of these substances 

 removed from the body in 24 hours, either in the 

 perspiration , or in the excretions, amount to about 

 five ounces, containing 350 grains of nitrogen ; and 

 this Avaste at least must be made up by the gluten, 

 fibrin, or other protein compounds of the food. 



In the 15 lb. of wheaten bread, supposed in the 

 previous section to be eaten to supply the carbon 

 given ofi:'by the lungs, there Avill be contained also 

 abjut 3 ounces of gluten — a substance nearly 

 identical with fibrin, a.nd capable of taking its place 

 in the animal body. Let the other two ounces 

 wliich are necessary to supply the daily waste of 

 muscle, &c., be made up in beef, of which half a 

 jiound contains 2 ounces of dry fibrin, and we 

 have — 



For For waste 



respiration of muscle, &c. 



IJ lb. of liread yielding 18 oz. starch and 3 oz. of gluten. 

 8 oz. of beef yielding •• 2 oz. of fibrin. 



Total consumed by ' 

 respiration and the 

 ordinary waste. 



18 oz. starch and 5 oz. ■ 



jluten or 

 fibrin. 



If, again, the 7^ lbs. of potatoes be eaten, then 

 in these are contained about 2.| ounces of gluten 

 or albumen, so that there remain 2^ ounces to be 

 supplied by beef, eggs, milk, or cheese. 



I'he reader, therefore, will understand why a 

 diet, which will keep up the human strength, is 

 easiest compounded of a mixture of vegetable and 

 animal food. It is not merely that such a mix- 

 ture is more agreeable to the palate, or even that 

 it is absolutely necessary — for, asalready observed, 

 the strength may be fully maintained by vegetable 

 food alone ; — it is because, without animal food in 

 one form or another, so large a bulk of the more 

 common varieties of vegetable food reqiiires to be 

 consumed in order to supply the requisite quanti- 

 ty of nitrogen in the form of gluten, albumen, &e. 

 Of ordinary wheaten bread alone, about 3 lbs. 

 d lily must be eaten to supply the nitrogen, f and 

 there would ♦^hon be a considerable waste of car- 

 bon in the form of starch, by which the stomach 

 would be overloaded, and which, not being -vforked 

 up by respiration, would pass oS" in the excretions. 

 The wants of the body would be equally supplied, 

 and with more ease, by 1| lb. of bread, and 4 

 ounces of cheese. 



Oatmeal, again, contains at least one-half more 

 nitrogen than the wheaten flour of our climate 

 and lience 2 lbs. of it will usually go as far 



