FLESH-FORMERS.

Lyttelton Times, Volume LIX, Issue 6869, 6 March 1883, Page 3

FLESH-FORMERS.

{English Paper.) The moit fundamental, and at the eame time the most «i*ful, clawification of foodstuffs » thst which arrange! them in four main groups, distinguished frsea each other both by their different chemical compositions and by th«ir diverre physiologies! effect*. These groups are respectively known ae (1) the albuminoid*, proteidi, or flesh-formers j (2) the amyloid*, carbohydrate*, or heat* Sivers j (3) the oils or fate j (4) the mineral odiei, salts, or ash. Examples of the second group are starch, sugar, gum, dextrin ; cilscr fate occur in ail meat, *-» well ae in many vegetable product*, particularly in seeds, such ae hazel-nuts, walnut*, cocoa-nute, and pineseeds ; the mineral foodstuffs include water, common salt, and various other inorganic compound*. The group comprising the albuminoids, or fleih-formers, present* a sharp chemical distinction from the other groups is that rh» albuminoids all contain nitrogen, and for this reason they are often referred to as the nitrogenous foodituff*, or as the nitrogenous compounds in foods. This element nitrogen » the inert gas that forms four-fifths of the bulk of the atmosphere, and it is also noted as being far mors abundant in animals than is vegetables; it is likewiae present m such familiar substances as nitre (saltpetre), nitric acid, and ammonia. The other elements present besides nitrogen are carbon, hydrogen, and oxygen, so tha' all albuminoids a*e made up of these four elements variously combined, with or without e> email quantity Or sulphur and phosphorus. Amongst the commonest albuminoids are albumen, fibrin, and casein, each of which merits a few words. Albumen is the chief solid constituent of white of egg, and gives its name to the entire group. It is preienfc in the blood of many animals, and is a cote mon ingredient of most vegetable juices, being found in considerable quantity in certain seed*. It exists in two states, one soluble in water, the other insoluble. By heating the- liqnid containing the soluble form, it becomes insoluble, as is seen when an egz in boiled or poached. Addition of nitric acid wi.i produoe the same result. Albumen may be dried into a pale yellow mass, waich is very friable, and has neither taste nor smell. 100 carts of the dry substance contain carbon, 63 5, hydrogen 70, nitrogen 15 5, sulphur 16, oxygen 224. Fibrin likewise occurs in both plants and animals. In the wheat grain we find, for example, about 10 per cent, and in beef-mnicle, free from fat, about IS. Fibrin obtained from different sources varies in proportion and in competition. The names of the chief animal fibrins aro bisod-fibrin found in blood, and myosin and syntonin in muscle. Fibrin may be isolated fjr examination either by washing blood-clots, or by whipping blood with a bundle of twigs and then washing. Casein formsthree-fcurthsof the nitrogenous matter of milk, it is also present in the yolk of eggs, while the so-called legumin of peas, beans, and other pulses is nearly identical with, or closely similar to, casein. It differs from the other albuminoids by the ease with which, even such weak acids as acetic (of which Tinegar is an example) cause it to-coagulate, as is familiarly evidenced in the formation of the curd in cheese-making. When eaten alone by adult animals casein has a very constipating effect.. Beudce tJio thisvo wo Wo a»enUox>««t fcbare are other leas abundant albuminoids in the flesh of animals, and in the fiuHa of their bodies. A very interesting and important ono is haemoglobin, which differs from its allies in containing a small quantity of iron % it constitutes the red colouring matter of the blood, in tee nutrition and aeration of which it discbargaa a most essential function.

We may now consider the albuminoids from a physiological point of view, and inquire to what utes they are put in the bodies of animals. In the first place, they serve to build up and repair tho nitrogenous tissues of the body, especially muscular fibre, which forms the basis of all Cash ; si no other ingredient of food can do this, it is right and proper that the albuminoids should be called flesh-formers. Next, they contain about 10 per cent moie carbon than is present in starch and sugar, and eocue of this (only a portion, however) is available as a source of heat and work in the body, bo that if, in a food, the supp'y of carbohydrates falls short, the albuminoids can make up for the deficiency. But, since the carbahydrates contain no nitrogen, it is impossible for them to do duty for in the work of flesh-building, vad this is the reason that a dog fed solely on pore fat would waste away and die. Thirdly, the albuminoidj may aid in tho production of fat in the body, for although they do not contain fat as such, they nevertheless contain the elements carbon, hydrogen, and oxygon, which make up fat, and in the chemical changes to which they aro subject in the animal body albuminoids may and do get broken up into fatty substances on the one hand; and bodies rich in nitrogen on the other. As the various albuminoids occurring in grain, roots, and other vegetable products are quite similar in composition to those found in milk, blood, and flesh, it follows that a'l animals—our horses, cattle, and sheep, w well as ourselves, our dogs, and our cats, eat the same kind of flesh - forcing compounds. From these are produced not only the albuminoids of the animal body, but the hair, wool, horn, and, as we have already seen, to some extent, the fat. Tho oxidation of albuminoids iu the body leais also to the pro- • duetion of animal warmth, and to the development of raeshanical force, whereby the animal is enabled to do work. Consequently, albuminoids supply in themselves all, or nearly all, the requirements of the aaimal body, so that they approach a degree of perfection quite unparalleled br any other ftod constituent. Even when the animal does no work, or is not laying on flesh, it yet requires a certain constant quantity of albuminoid food, to replace tho nitrogenous wajte of the body which is always going on. Tins nitrogenous waste forms a compouud named urea, which is secreted in the kidneys, the urine containing 2 2 per cent of this waste product in solution. Tho following table shows the percentage of albuminoids present in tome of the commonest feeding-stuff* of 4he farm:—

Deco'tioated Cotton Barley 10(3' Calto 41-2 Make 10* Linseed Cake ... a-t'l Meadow Kay ... 0 7 Bwros.. 25 - 5 Bean Straw «3 Undecorticated Cot- Brewers" Grains ... 4'B tonCako 216 Meadow Grass ... 35 Malt Dust ... ... 237 tiireon Clavor ... S 3 Peas 'ii'i "Wheat Straw ... 30 ■Whoatßrau 14i! Potatoes 21 Oats 129 Swedes IS Clover Hoy ... ft W'S Mangles 12 Wheat 11-3 Turßlps M