There is a peculiar form of anaemia, different in its origin from the preceding, in which iron is scarcely less effectual. I allude to the condition of system often left behind by miasmatic fevers, characterized by a sallow paleness of the surface, general languor and weakness, mental depression, feeble digestion, and often more or less dropsical effusion, sometimes only anasarcous, but sometimes also in one or more of the serous cavities at the same time. There may or may not be attendant disease of the viscera. I believe this condition to be a pure anaemia, resulting from the destruction of the red corpuscles of the blood by the miasmatic poison; the yellowness being attributable to a changed condition of the liberated hematosin. The same condition often follows yellow fever, probably from the same cause. It is delightful to see how rapidly this condition, serious if not relieved, will yield to the conjoined use of iron and quinia. Slight cases will often get well in a week or two, the worst generally within two months. When there is considerable dropsy, however, bitartrate of potassa, to the amount of an ounce, taken through the day, should be associated with the other medicines.

In a large number of diseases, iron is given with a view mainly to the correction of the anaemia with which they are associated. The following list embraces most of them. When, in any one of them, there is an additional indication for the use of the medicine, the fact is mentioned.

Scrofulous affections are often attended with a poverty of the blood which serve- to sustain the diathesis, and aggravate the complaint. But there is often also a relaxation of the tissues in these affections, which calls for a joint tonic and astringent action in the remedy. Iron answers both indications; and is very often, therefore, given in the different forms of scrofula. It has,' however, no specific influence over the disease, and is used only as an adjuvant to the alterative remedies, such as iodine and cod-liver oil. The iodide of iron is generally preferred, on the presumption that the effects of the iodine may be obtained along with those of the chalybeate.

Phthisis may be ranked among the scrofulous diseases, and might be supposed to call for the remedy equally with the other forms. But there is a consideration connected with this affection, which renders caution in the use of the chalybeates necessary. The anaemia in phthisis is a pro-vision of nature for bringing the blood into a due relation with the capacity of the lungs. If, with the progressive destruction of these organs, the blood should remain undiminished, the quantity passing through the lungs would be more than could be duly oxidized, or indeed carried through the remaining pulmonary vessels. Congestion of the lungs, with hemorrhage, and other evils from a want of due aeration of that fluid, would take place. The use of iron, if successful in its object, might counteract this purposed of nature, by inducing a relative plethora. Nevertheless, the anaemia is often carried far beyond the point essential for its useful purpose; and, in such cases, the chalybeates would be serviceable by lending the support of good blood to the exhausted functions, and even by obviating, in co-operation with other measures, in some degree, the disposition to tuberculous deposition. But they should be omitted, as soon as the blood may be deemed to have become as much enriched as the condition of the lungs will permit, without risk of mischief.

Various nervous affections offer indications for the use of chalybeates Disorders of the nervous system are often nothing more than results of the irritation of the nervous centres, sustained by the constant call made upon them by the functions when suffering from the want of blood. Placed as points of communication between all the functions, and the various agencies intended for the supply of these functions with the means of support, they are constantly receiving impressions, and sending forth influence; and, the degree of their excitement being in proportion to the amount of impression received, they are consequently most excited when the wants of the functions are the greatest. Hence, in an anemic condition of the blood, when all the functions are suffering under the deficiency of this essential pabulum, the nervous centres are necessarily over-excited, and exhibit their irritation by various violences throughout the system. By correcting the condition of the blood, the functions are quieted, the nervous centres are relieved, and the existing obvious disease, so far as it depended on their irritation from this cause, ceases. Hence the use of iron in these complaints. But it operates also on the tonic principle of giving strength to the nervous centres, and enabling them, in a certain degree, to resist the irritative impressions made upon them; though, in this mode of action, it is inferior to the preceding section of mineral tonics, including the preparations of silver, copper, and zinc, which have the advantage over the chalybeates of a special influence upon these centres, not possessed by the latter remedies, or, at all events, in a less degree. The chalybeates, therefore, while they are much more energetic and more relied upon in the nervous diseases, when dependent on or aggravated by anemia, than the other metallic remedies mentioned, are inferior to them under other circumstances. The rational practitioner, guided by this principle, will know when to rely mainly on the chalybeates in these complaints, when to use them as adjuvants of the other metallic tonics, and when to abstain from them as useless possibly injurious; for, of course, they could do only harm in irritation of the nervous centres dependent on or aggravated by plethora.

Hysteria is one of the affection- in which chalybeates are often used advantageously on the principles above stated.

Neuralgia is also frequently benefited by them; and, in many instances of this complaint, they are among the most effectual remedies In the treatment of neuralgia of the face, or tic douloureux, they enjoy a very high reputation; but, no matter what may be the seat of the complaint, provided it can be traced to anaemia as the sole or a co-operative cause, they will prove equally beneficial. In gastralgia. they sometimes act very favourably. They are often associated with the narcotic extracts, as of belladonna, stramonium, and conium; and there is probably on the whole, no more effectual combination in the treatment of neuralgia.