and the season of the year; in winter a period of twenty-four hours is decidedly preferable. At the end of this period the cream will all have risen to the surface and must be carefully skimmed off, after which operation the skim milk will remain fit for use. In close sultry weather in summer, unsuitable for keeping milk for any length of time, without fermentation and coagulation taking place, unless placed in a very cold situation and surrounded by ice, it may be allowed to stand eight or twelve hours. But if this brief period should be too short to separate a sufficient quantity of cream, on account of the milk being very rich in the latter, it will be necessary to pass it through a filter, by which, as already stated, the fatty matter is almost entirely removed.

In the manner just indicated, the milk globules and a very large proportion of the minuter butter particles are removed; but unless filtered there still remains some fatty matter in a molecular condition suspended in the skim milk and imparting an opacity to it; but when proper care and attention have been bestowed in its preparation, the amount is so very small as not to affect in an appreciable degree the favourable progress of the treatment in the great majority of cases.

Skim milk thus obtained is a simple solution of

casein, of milk-sugar, and of certain fixed salts, in water, with the addition of a very small quantity of fatty matter, or butter, in a state of mechanical suspension; its specific gravity, which can be readily ascertained by the urinometer, should, in good cow's milk, range between 1030 and 1040; when below the former figure it has been diluted with water.

The quantity of casein, or flesh-forming material, capable of being absorbed and converted into blood immediately after digestion in a pint of skim milk of good quality and undiluted with water, in round numbers exceeds half an ounce, and in good specimens approximates to near three-quarters of an ounce, and to this is added all the salts necessary for the nutrition of the body, and milk-sugar as a heatforming substance. It is therefore quite obvious that starvation, or any approach to it, on an exclusively skim milk diet is altogether impossible, when a quantity varying from five to eight pints is taken daily by an adult, especially by an invalid not subjected to much exertion. On the contrary, experience demonstrates, as I shall have occasion to point out further on by means of illustrative cases, that such a diet is not only capable of supporting life, but also, that individuals previously incapacitated for exertion by disease, have, after living on it exclu

sively for a period of several weeks, become strong and vigorous, and capable of great exertion without suffering fatigue. I feel desirous of directing particular attention to this fact, because of the opposition to the treatment too frequently encountered in practice, from the ignorance and prejudice of certain persons who regard it with suspicion and cannot believe it possible that life can be supported on what appears to them to be such slender fare. On such individuals, ignorant alike of the rudiments of physiological science and the chemistry of food, argument is lost; it is in vain to endeavour to enlighten their understandings by pointing out that the richest and most nutritious kinds of solid food, served up after the most approved methods of cookery, must first, by the process of digestion, be reduced to a condition. quite as liquid as milk, before they can possibly be absorbed into the blood and contribute to the nourishment of the body, and that even then, they too frequently import into the blood the elements of disease and future death. Skim milk is free from this latter vice, it simply conveys what the tissues of the body require and appropriate by a healthy nutrition, and nothing more.

These observations on skim milk lead to a consideration of its therapeutic action, and as it contains

no special therapeutic agent, the question at once presents itself, to what are we to attribute its curative power over certain diseases? In endeavouring to answer this question, it is of course necessary to take into consideration the pathology of the particular diseases over which it has been ascertained to exercise so powerful a control. Now of these diseases, when taken in the aggregate, it may be predicated, that they are intimately associated with a depraved or morbid condition of the blood; with deficient or perverted nutrition, or with mal-assimilation. Of the various diseased conditions to which I refer as belonging to this category, I may specially mention fatty degeneration of various organs, Bright's disease, and other affections associated with a poor watery condition of the blood, and diabetes; this last affection, in the present deficient state of our knowledge of its pathology, may with strict propriety be termed one of mal-assimilation.

The curative influence of skim milk over these various, and in many respects dissimilar, forms of disease may, with great probability of correctness, be referred to two causes :

First, to the facility with which, by the processes of digestion and sanguification, it is transformed into healthy blood, which seems to have the power of

regulating or controlling a healthy and of preventing a diseased nutrition, in accordance with physiological laws.

Secondly, to the absence of all substances foreign to healthy nutrition, and which, when imported into the blood with the food, become materies morbi, or the appropriate sustenance of morbid action or disease.

This appears to be the only explanation it is possible to give.

In addition to these effects on the blood, skim milk has the special property of acting as a powerful diuretic when taken in sufficient quantity (partly on account of the water it contains), which makes it a valuable remedy in general dropsy; but this action, as I shall show when considering the treatment of Bright's disease, is intimately connected with and in a great measure the result of its action on the blood serum, by restoring its lost albumen and its natural specific gravity.

Although it is not intended in this work to treat of all the special applications of the skim milk treatment, yet it is important to mention that it is invaluable in functional derangements and diseases of the gastric and intestinal organs, especially in certain forms of dyspepsia, hypochondriasis and diarrhea;