milk in жик

necessary in the rearing of children, especially if there is no one by her side to direct her. It is better to choose, for a nurse, a woman who has suckled other children.

We should first inquire into the period of the confinement of the nurse, that is to say, into the age of the milk. In fact, this liquid changes its character in proportion as the time from the period of delivery increases, and it is no longer suitable for the young child which has been just born. It does not possess the laxative properties of the milk first secreted after birth; it does not contain any colostrum ; it is nearly always an indigestible and slightly abundant aliment, the use of which should not be recommended. It is said, it is true, that a young child renews the milk, because the breasts become distended 6 afresh, and because nearly all the phenomena of milk fever are observed. This is incorrect, or at least is not proved by chemical and microscopical analysis. The enlargement of the mammary gland only takes place in this case, because the new nursling does not consume so much milk as the first one did.

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We should always make choice amongst nurses of those who have been confined from about six or eight months, and whose age ranges between twenty and thirty-five years. They rarely possess the desirable qualities when their milk is older, and their age more advanced. A table, introduced further on, will demonstrate in a precise manner the influence of age on the composition of the milk. They should have brown or black hair, in preference to flaxen or red; these last have generally a large supply of milk, but it is serous, as the analysis of MM. Vernois and Becquerel demonstrate. They should possess rounded and plump figures; the bosom well formed, slightly firm, and marbled with blue veins; the gums of a good colour; and the teeth in good condition. However, the character derived from the soundness of the teeth does not possess so much importance as was formerly attached to it. There are women who have bad teeth, and who, yet, are excellent nurses. There are others, on the contrary, who, with very good teeth, have an enfeebled constitution, which prevents them undertaking lactation.

The red colour and firmness of the gums possess much more importance, in the eyes of medical men, than the soundness of the teeth. From the state of these parts, we judge of the strength of the subjects, their state of health, and, to a certain extent, the qualities of their blood. It is evident that colourless gums belong to a woman whose blood is watery and impoverished; who might, notwithstanding, be in a tolerable state of health, but who would always make a bad

nurse.

It is necessary to make choice of a woman of a sweet disposition, and whose intelligence is sufficiently developed to superintend the

child which is intrusted to her care. Good humour in nurses cannot

humer them from their sufferings. They then, consequently, assume habits estable

be too much sought after; it serves to amuse children, and to distract

of light-heartedness and cheerfulness, which have always a happy influence on the development of their mind and disposition.

Nurses should be carefully examined with respect to their constitutions, and to their health; they should even be inspected, as far as decency will permit, to assure ourselves that no cicatrix, nor mark exists, which indicates the actual or former existence of a rachitic, scrofulous, leprous, or syphilitic disease. The anus, genital organs, and interior of the mouth-parts which are especially the seat of the syphilitic disease, should be examined.

With respect to the nurses whom we examine, it is evident that we must take into consideration the same circumstances, which are admitted with respect to mothers, as preventing them from suckling; and we must seek—a difficult task-in their family and on their word, information which may throw some light on the existence of hereditary diseases. This investigation is often useless; the women know nothing about the subject, or pretend not to comprehend it. No positive result is arrived at. This is an additional motive for very great care in the local examination of the nurse who presents herself.

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We must also be assured that the milk is sufficiently rich in nutritive elements, pure in its composition, and sufficiently abundant; this is very readily accomplished by means of chemical and microscopical analysis. However, we must not be mistaken on the value of these researches; they lead to valuable results as regards the material and physical qualities of the milk, but they give no information, if I may so express myself, on the nature of the vital qualities of this iter! liquid. In fact, the milk secreted by a woman tainted with syphilis, does not differ, microscopically, from the milk of women of a gouty, lymphatic, or any other race. The virus exists in the milk, but it is there present in an imperceptible form, and no one has yet been able to demonstrate its existence except by its effects. Consequently, if it is necessary to examine the material richness, that is to say, the physical and chemical qualities of the milk, they should be compared with the vital qualities-a double appreciation necessary in the choice of the nurse.

Before treating of the characteristics of richness and of poverty of the milk, it is necessary to enter into some details on the nature of this liquid, and on its composition in its normal state.

ON THE MILK.

According

The milk contains the principal elements of the food. to the idea of Dr. Prout, the milk is the type of perfect food.

It is understood that no substance can merit this title, that is to say, is capable of sustaining life and health, without it contains various salts, and at least two proximate principles, one combustible, the other of an albuminous nature.

In fact, the muscles, the cellular tissue, &c., of the animal, have not only to be repaired, but at the same time the necessity of calorification must be provided for; its bones, the nervous matter, the acid or alkaline humours, must also be renewed.

Thus the milk which is destined to constitute the sole nourishment uty of the young mammalia, contains the three kinds of substances alluded

to, namely

931st. An albuminous matter, the caseum.

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2nd. Two combustible substances; one fatty, which takes the name of butter; the other, saccharine, called lactine or sugar of milk. 3rd. Mineral substances dissolved in water; amongst which must be mentioned chloride of sodium, alkaline and earthy phosphates, and the oxide of iron.

These constitute the elements of the milk; but a precise idea of this secretion will only have been obtained, when we state in what condition these substances are there observed. To arrive at this information, microscopical and chemical analysis are absolutely necessary.

State in which the principles of milk are observed. It may be observed that the milk is composed of a liquid and of a solid portion; or if you will, that it is water holding globules of butter in suspension, and caseum, sugar of milk, and salts in solution.

The globules of butter are characterized by being spherical, smooth, perfectly transparent (when they are isolated), and limited, as it were, by a black circle, which is only the effect of the refraction of light. By their coalescence, they form white masses; it is their larger or smaller number which gives to the milk its greater or less degree of opacity.

These globules, which may attain the diameter of about 0.01 of a millimètre, are only visible by means of a powerful instrument. Moreover, in the same milk, they possess a very variable size, and no very great difference is to be observed, in this respect, between one kind. of milk and another.

Normal matters: but which may be considered as accidental in the milk. The globules of butter, usually isolated or free, sometimes coalesce into small groups, doubtless by means of a mucous matter secreted by the lactiferous canals.

The microscope, moreover, demonstrates in the milk, scales of epithelium, detached from the mucous membrane which lines the above canals.

These constitute the accidental substances which do not form an essential portion of the secretion now under consideration.

After all, then, in the present point of view, the composition of milk may be compared to that of blood, which is formed of globules suspended in a solution of fibrin, albumen, and salts.

But this comparison, pushed further, would not be sufficiently exact; alty for, to speak correctly, milk is only a simple emulsion of fatty matter tion in ac in water, rendered more viscous by the caseum; whilst blood is distinguished by albuminoid corpuscles, endowed with organization.

A decided difference, then, exists between these two animal liquids, which cannot be diminished, even by admitting, with Leuwenhoeck, that a small portion of the caseous matter of milk is there present in the solid state, under the form of globules.

Comparison between the milk and the blood. There is another and a more philosophical manner of examining the composition of milk in relation to that of blood; this consists in looking upon this secretion as a fluid formed entirely at the expense of the latter, which contains its elements ready prepared.

In fact, is it not known that blood contains, under the same forms, all the earthy matters of milk?

In the second place, the caseum is the albumen of the blood, the molecular condition of which is alone changed; and, moreover, caseum has been already discovered in the blood of a great number of animals.

Besides, the presence of fatty matter in the blood, under the form of globules, is now no longer doubtful.

Lastly, the existence of lactic acid has been demonstrated in the blood of those animals whose milk contains lactine.

The milk is, then, derived from the blood, which it resembles in all the principles it contains-earthy matters, caseum or albumen, fatty matter, and lactic acid; and from which it differs in all those which are wanting fibrine, colouring matter, &c.

After this comparison, I shall add one word on the condition of the in caseum, in the serum of recent milk, filtered so as to separate the globules. This principle is not there present in a state of simple solution, since it appears to be insoluble when it is pure; it is held in solution by means of the soda which the milk contains. In this Suliucn combination, the caseine plays the part of an acid; but of an acid of such slight intensity, that the base manifests its properties nearlys Jotta as if it was free, and gives to the milk, especially that of the woman, a decided alkaline reaction.

On the changes which take place in the milk after its extraction. The milk is usually alkaline; it only becomes acid after fermentation has commenced, a portion of the sugar of milk being transformed into lactic acid.

When the quantity of this acid is sufficient, the caseine displaced from its combination separates in the form of curd.

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But generally, previous to this, another phenomena is manifested in the milk which is exposed at rest to the air; the oleaginous globules come to the surface and form a layer, of greater or less thickness; and in this state, combined with a certain proportion of caseum, they constitute the matter known under the name of cream.

In cream, the globules of butter, moistened by the liquid portion of milk, are at a certain distance from each other; by churning, their junction is effected; and they coalesce into a compact mass, which constitutes butter, properly so called.

On the variations in the composition of milk. What has just been said, is sufficient to indicate, in a general manner, the composition of milk amongst all the mammalia; but it undergoes modifications according to the species, according to the individuals, and according to circumstances in the same individual.

Moreover, recent experiments lead us to believe, with more probability than ever, in the existence of certain common features which characterize the milk of all animals belonging to the same natural group.

Thus the saccharine matter, which, it may be said, is not absolutely necessary, is only present in animals which live exclusively, or at least in part, on vegetable food; amongst the carnivora, its presence is doubtless supplied by a more abundant fatty matter.

The composition of milk varies, especially in relation to the proportion of its principal constituents. In one species, caseum preponderates, in another, butter, or sugar of milk. Place, for example, the milk of the cow and that of the woman side by side; the first is richer in caseum; the second exceeds it in the proportion of butter and sugar of milk.

The young calf, which has to walk as soon as it is born, sucks a milk which is very suitable for the production of muscle, since it is very much charged with azotised matter; the child, on the contrary, which is not necessitated to test its strength so early, and which, in consequence of this inaction, is deprived of a source of heat-the child, I say, receives a milk which is poorer in caseum, but richer in the combustible substances, butter and sugar.

This hypothesis is perhaps too bold; it is, at present, merely an idea which requires to be verified by observation and experience. Modifications in the special characters of the proximate principles of the milk also cause its composition to vary.

It is certain that different kinds of butter may be recognized according to the nature of the volatile fatty acid found in them, which is in part free, in part combined, and to which each one owes its peculiar odour. In the cow, &c., it is butyric acid; in the goat, caproic and capric acids. Various sorts of caseine may also be admitted: the caseine of the milk of women, does not react like that of the milk of cows.