remedies which are necessary at other periods of life to relieve irritation alone.

All questions of practice in these instances are manifestly those of degree; nor can any rule be given general enough to preclude attention to the individualities of each case. We have often, too, in old age other symptoms, which seem more directly to require the aid of opiates; such as habitual restlessness at night, under the influence of vague images and sounds, harassing the mind by a sense of reality beyond that of dreams. The effect of the remedy, however, even in these instances, is by no means an assured one; and benefit can be attested only upon trial. For progressive or permanent changes in the brain are generally concerned in such cases, and of a nature often to render injurious the stupor produced by narcotics, as well as to make uncertain their effect in procuring repose. There are doubtless cases where it is otherwise; but it is difficult to find other criterion than that of experience for determining these.

In the eneuresis of old age, especially when not depending on any disease of the prostate gland, I have often found more benefit from moderate opiates than from any other remedy. And in that harassing complaint, the prurigo senilis, which is ever so difficult of relief, this treatment is probably the best. Where the internal use of opium is objectionable on any account, the irritation may be greatly abated by lotions or ointments in which this is the main ingredient. Its combination with some mild mercurial, under the same form of use, frequently adds to the benefit obtained.

The principles as to diet in old age do not differ essentially from those applicable to every period of life. The questions are chiefly those of degree, and to be answered under the same modifications and exceptions as in other cases. Regularity in the times of food seems indeed, as in infancy, more

essential to the well-being of the system than when the body is in the full vigour of life. It has now fewer resources, whether animal or vital, for righting itself: the functions are all less prompt to repair any partial injury or deficiency. Stimulants also, which either in kind or quantity might be injurious in middle age, are often fitting or needful at a more advanced period. The questions as to particular articles of diet may for the most part be settled on the same principles for both these periods; making due allowance for the difficulties of mastication in old age, and for the want of those active exercises of body which tend to obviate obstruction, and to assist all the powers, mechanical as well as vital, upon which digestion depends.

All that relates to the preservation of warmth in old age, and, through this, of equable circulation, is too familiar to need being dwelt upon. The functions upon which animal heat depends have lost their vigour; and its production is in the same ratio diminished. We are bound with the greater care to save from loss by diffusion that which remains. This is important, not alone as sustaining the functions of the skin, the action of the limbs, and the general comfort, but also as lessening that tendency to congestion in internal organs which is one source of particular maladies, as well as a cause of general decay. We cannot restore the balance between absorption and deposition, in the loss of which some define old age to consist; but if these changes admit of retardation, as it is likely they do, this is probably best effected by whatever tends to maintain animal heat, and a free circulation throughout the vascular system.

Connected in some sort with this latter topic is the common question respecting old age (but one of deep interest, though common), to what extent the bodily powers may be preserved by maintaining their assiduous exercise:- whether, to take a

single instance, the muscular organs may be longer kept in vigour by exertion to the full extent of ability at each successive period of life? or whether the powers, whatever they be, which minister to their actions, are longer and better maintained by comparative repose?

Though the inquiry may seem easily answered by common observation, yet is this not so. It involves some of the most subtle and obscure points in physiology; those, to wit, which regard the nature and origin of vitality, its mode of distribution and manner of decay;— questions which, under different forms and various phraseology, have perplexed reasoning men of every age, and begotten theories and controversies without end. Taking life, however, not as a definite exhaustible quantity of an unknown influence, but as expressing a common result of the actions of many parts differently constructed and endowed, we are furnished with what comes nearest to a satisfactory reply. Whatever habits of living sustain the greatest number of organs or functions in healthy state (having regard also to the relative importance of these functions) may be considered as most conducive to length of life. The positive fatigue of any organ from its exercise must always be deemed an excess;-of little import, it may be, in single instances; certainly injurious by frequent or habitual repetition. All exercise of a natural function of the body within this limit may be viewed, without material risk of error, as salutary in itself, and maintaining the integrity of the organ concerned longer than the opposite habit of inertness and disuse.

This practical distinction is simple, and probably just. It is applicable, moreover, to every period of life, and very appropriately to old age in all its stages. The limit of action. without exhaustion becomes more and more contracted, and in the same ratio must action be abated in degree. Exercise,

short of this exhaustion, and with due allowance for casual fluctuations of power, may be admitted as maintaining the functions in their healthiest state, and thereby tending to lengthen the term of duration to each.

The same principle and rule may be applied without error to the mental functions also. Here, equally, there is a power, naturally diminished in old age, susceptible of exhaustion from excess of use, and liable to be permanently impaired where this excess is frequent and severe in degree. On the other hand, disuse is not preservation; and we have every cause to believe that the integrity of these faculties is best and longest sustained by habitual exercise, within those bounds which are reached without fatigue at each successive period of life.

With all the desire that has existed to discover rules conducive to length of life and preservation of its powers, it is doubtful whether any can be found which are not directly subordinate to the principle just stated. We have no simple element, cognisable by our means of research, to deal with here. Organs and their functions are the sole interpreters of life to our present reason; and the maintenance of these in healthy action is all that can be done to solve the problem, and satisfy the desires, which have been entertained by mankind of every age on this subject.

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CHAP. XX.

ON THE USE OF EMETICS.

AMONG the changes which time and fashion impose upon the treatment of disease, Emetics as a remedy have fallen into comparative disuse in English practice. It is no longer now, as heretofore, one of the first questions before the mind of the practitioner, when called to prescribe for a disorder, whether the stomach should not be immediately thus relieved. The suggestion of the patient himself is for the most part needed, or some other equally express indication, to lead to their use. I am speaking here only of a general alteration that has occurred. The exceptions to it are of course numerous; but the truth of the fact so stated will probably not be denied.

The cause of this change may chiefly be found in that larger and more various employment of purgatives which forms the character of our modern practice. To what extent is the alteration of method a beneficial one? I believe a fair consideration will justify the opinion that in many points it has been carried too far. Vomiting, especially when brought on at the outset of fevers and many other diseases, produces effects of a kind, and with a speed, which no purgatives alone can equally obtain. Beneficial as is the action of emetics in unloading the stomach and upper part of the alimentary canal, it is certain that their influence goes far beyond this; and that other parts of the body, even the most remote and different in structure, are powerfully acted upon.