secreted, called colostrum, possesses a purgative quality evidently intended by the all-wise Author of our being for the purpose of removing the meconium[A],—a process which experience has sufficiently proved to be necessary for the welfare of the newly-born infant. Afterwards, ceasing to possess this aperient property, it is calculated solely for affording nutrition; and finally, at a certain period from delivery, it gradually becomes impoverished, loses its former healthy qualities altogether, and acquires others which are injurious to life. This important change, as above noticed, generally happens at a certain period after delivery; varying, however, somewhat in particular women, and in the same female on different occasions: but, from disease, or other circumstances, the milk may become deteriorated before the time to which reference has just been made. If, for instance, the mother labour under any serious disorder, it is universally admitted that her milk may also become unhealthy; and this may take place even a short interval after delivery.

Although we cannot explain how the brain and nerves act, and probably never shall be able to do so, yet we are well aware that their influence is absolutely requisite for the healthy performance of every function in the human body.

That mental inquietude will impede digestion is a fact familiar to almost every one; but, I believe, it is not so generally known, that it will with no less certainty retard and alter the nature of the secretion furnished by the breasts of the lactescent female. Violent affections of the mind will cause the milk to become thin and yellowish, and to acquire noxious properties: even the fond mother's anxiety, while hanging over the couch of her sick infant, will be sufficient to render it unfit for the sustenance of the object of her solicitude.

The state also of the stomach and bowels and the diet of the nurse materially and constantly influence the nature of the lacteal secretion.

The milk, besides, is liable to deterioration from another cause, namely, the recurrence of the usual periodical appearance—for should this take place in a nurse, it is agreed that her milk is liable to produce disorders in the child who imbibes it; which could not happen, if the former possessed its ordinary component parts, and retained its natural properties.

The recurrence, moreover, of pregnancy in the lactescent female may render the milk of a bad quality, and will invariably lessen its quantity. Mr. Burns asserts that in these cases the milk 'does not become hurtful,' but in this opinion I must beg leave to differ from him; since I have repeatedly seen it, from this cause, palpably altered in appearance, and have observed diarrhœa and great debility produced in the children who were suckled with it.

An almost universally received opinion among females, and, indeed, one very frequently entertained by members of the medical profession, is, that while a woman continues to nurse her infant she will not again become pregnant; but this, as a general proposition, is unquestionably erroneous; it is even doubtful whether such opinion will hold good in a majority of instances. The continuance of lactation will very generally, it is true, tend to prevent the recurrence of the periodical phenomenon; yet, nevertheless, it will not in every instance prevent pregnancy[B]. Should, however, a woman with an infant at the breast again become pregnant, (a circumstance that very frequently occurs, and of which, from the general though not invariable absence of those criteria by which this fact is accustomed to be recognised, she is not aware until it has made some progress,) one of two things will usually take place; either she will miscarry, or her milk will become impoverished in quality and diminished in quantity. Nor is this wonderful:—it was not intended by Nature that the processes of pregnancy and lactation should go on simultaneously, but, on the contrary, that the one should commence when the other had terminated; and experience sufficiently proves that they will not proceed well together: the reason of which, as it appears to me, may be easily given. During pregnancy, and particularly during its latter periods, the vessels of the womb gradually enlarge, and a much greater quantity of blood than usual is determined to that organ for the increase and perfection of the embryo and its appendages; which, after delivery, becomes transferred to the breasts to supply the material for the secretion of the milk: but if, during pregnancy, lactation be also persevered in, the blood becomes directed at the same time to two different parts of the body, somewhat remote from each other, namely, to the womb, and to the breasts; hence, neither is likely to receive its due proportion of this vital fluid, and, consequently, the functions of one or the other, or both, are liable to become impeded or suspended. If the breasts continue to receive a sufficient quantity of blood, the secretion of milk goes on properly, but the womb is deprived of its necessary supply; the embryo, in consequence, languishes and dies, and, becoming an extraneous body, is thrown off, producing abortion; while, on the other hand, should the womb still obtain its due proportion of blood, the breasts are robbed of it, and the secretion of milk, if not altogether suppressed, is rendered either deficient in quantity or deteriorated in quality.

Finally, the breast-milk may become depraved and injurious by the process of lactation being continued too long, a practice which is, unfortunately, in this, as well as other countries, extensively prevalent.

I have not yet had an opportunity of examining the breast-milk in these diseased conditions except by the eye, and that rarely—but even this slight examination has enabled me to state, that it was greatly altered from its natural condition;—that it was more fluid than usual, and changed in colour, resembling a yellowish turbid serum, instead of displaying its well-known bluish hue.

I propose in future to attend carefully to this subject, and I would beg leave to recommend it as one well worthy the notice of those members of our profession who have made animal chemistry a particular study, having no doubt that they would be able, by a series of accurate experiments upon the breast-milk at different periods after delivery, and under various conditions of the mother, to collect many interesting and important facts—such, perhaps, as would tend very materially to augment our knowledge of pathology, and improve our practice in the treatment of certain diseases[C].

We cannot but believe that the Supreme Being has done nothing without an infinitely wise and good object, and it is obviously our interest, no less than our duty, to be guided by those indications of the Divine purpose which are distinctly to be traced throughout the creation.

It must appear evident to all who examine the matter in question, that the infant was intended to be nourished for the first few months of its existence through the medium of a fluid; because no teeth are provided to prepare for its use substances of a more solid description; and there can be no