It is clear, then, that the blood must be a fluid perpetually varying in its character and composition, as it is carrying to or from the body formative or excrementitious matters, even as a broad river bears on its surface to the remotest interior of a country all the supplies it may require, and carries off from every part its superabundance and its waste. But here the simile ends, the various matters are conveyed by a river along the surface of the stream, not mixing therewith, they do not, therefore, affect its integrity; but in the human economy, the various matters are not conveyed by the blood, but in the blood, and have become for the time a part of the circulating fluid, changing its character in various ways, but most essentially making it richer or poorer, and hence giving rise to a condition of plethora or anæmia. I shall say a few words on the first of these two conditions before examining the abnormal states of the organs of circulation.

PLETHORA.

A plethoric state of the body means, not only a condition in which the actual quantity of the blood is greater than is usual, or than is required, but also a state in which the blood itself, although not increased in quantity, is richer than ordinary, and fuller of

life serve to carry off any excess very easily, but when the meridian of life is passed, when the demands of the system for new formative matter has ceased altogether, and when the process of renovation goes on more slowly than heretofore, it is then that a plethora of blood is most to be feared and guarded against.

In proportion as the aged become less active both mentally and physically, lead a more idle and sedentary life, and yet indulge in diet-stimulating the appetite by exciting condiments, gratifying the stomach by large supplies of food, and neglecting to secure the regular and full action of the bowels and skin,-so will the blood become loaded with nutritive and formative matters far beyond what is required; be augmented in quantity, and richer in quality, and be forced through the body by the increased exertion of the heart, giving rise to hypertrophy of that organ; or be carried on by the arteries with difficulty, in the like manner distending them, and weakening their coats, increasing the calibre of the venous trunks, moving languidly through the capillary vessels everywhere, and ultimately in some organs, where the difficulty is greatest, producing a truly local plethora. When this occurs some overdistended vessel, somewhat weaker than the rest, may give way, and effusion of blood ensue; and thus is apoplexy of the brain or of the lungs induced, or some

needless: the signs of approaching as of existing plethora in the aged are so clear and unmistakable, that he must be most careless of his own health who allows it to become established, and does not at the first warning seek for the employment of remedial means.

The approach of a plethoric condition is often marked by insidious and deceptive signs, especially in the early period of age. There is a feeling of increased power a flush of the face and general surface, and a sense of plumpness and ease, which seem to imply high health, and which are regarded by the individual as flattering testimonies of that state and of the manner in which he resists the approach of the infirmities of age. This condition is, therefore, often not only misunderstood, but encouraged. An undue degree of exertion and exercise is pursued, and an undue quantity of food taken to support that exertion; and thus, for a time, an unnatural condition of the system is sustained, leading, however, to evil results. Such men are observed by their friends, and are thought by themselves, to be wonderfully well and active. Wise observers would say they are too well; they are in an unnatural state of perpetual excitement. Let Let persons between 50 and 60 years of age be careful of being too well and the more especially if this marvellous appearance of health, this marvellous accession of vigour,