This investigation would be incomplete without discussing the cause of death. The reader may smile and think how vague a term the cause of death must be when there are so many causes. To be more precise then, I purpose to inquire the mechanism by which the cause of death produces the effect, or death itself, and when we find that the same vital force which raised the body from a germ like the egg of a mite, and fashioned it to be a giant or a Homer, which fed it and made it strong for the battle of life, should be the same force which causes it when the last hour draws nigh to prepare the way for the extinction of earthly life in the frame, our wonder only rises higher at the functions performed by so simple a means.

Anaxagoras of Clazomene who first taught the heathen mind that the great promoter and ruler of the universe was a self-existent, immortal spirit, pure and incorruptible, told a stranger who was lamenting that he must die an exile far away from home, that it mattered little, for in every land the path to Hades was the same. I trust I shall be allowed to add to this sublime sentence that in every form of death the path is also the same.

Death people often say poetically is a long sleep, of which it is indeed but the cold and pallid image.* In the grave the good sleep the sleep of the righteous. Since poetry began, sleep and death have been counted twins, and the father of gods and men never distinguishes between them when he bids Phoebus Apollo bear his beloved Sarpedon to Lycia. Virgil made them half-brothers, and most men have cared little to disturb the verdict.

*"Quid est somnus gelida nisi mortis imago?"

Müller speaks of death as if it arose from the decay of the vital power. He says, "At some period or other this change necessarily ensues spontaneously in every living being; the state or influence which maintains the elements in their peculiar combination becomes more and more feeble, and is, at length, no longer able to counteract the tendency of these elements to form binary compounds among themselves and with other simple substances in the atmosphere." But it may be observed that here the decline of life is mixed up with the decay which ensues after death, and which in no way begins till after death.

The same writer throws out a conjecture but so carefully worded that he appears to say almost as much against his argument as in its favour. He observes that the increasing fragility of old age might arise from the products of decomposition constantly increasing as we get older, till their chemical affinity at last came to balance the vital force; but then he creates an obstacle to this which appears to me insurmountable, for he says, "in that case the vital force must diminish from the very commencement of life,” an assumption in support of which I see no proof. Dutrochet would have us suppose that the changes of old age depend upon the increasing accumulation of oxygen in the animal frame, but it does not appear that the accumulation of oxygen has ever been proved.

I believe that when life itself is studied by any unbiassed person, it will be observed that death in all cases simply results from the vital power being so completely withdrawn from the vital organs, by some agent which attracts it to one particular part or parts, that

their natural action ends, and that it has no power to set them in motion again. It matters not whether this agent is applied to a distant part of the animal system as in the case of electricity striking the heel, or prussic acid touching the tongue; whether it impinges upon a vital part as when a knife goes through the heart, or a frightful sensation calls the whole vital power to the brain; whether it is withdrawn by a rapid disorder as when the stomach is perforated by an ulcer or the slow attraction of a chronic abscess, the manner of action is the same.

The reader will naturally ask, Does this hold good of natural decay? I believe so, for this reason,throughout life we may trace a gradually increasing slowness in the mode in which functions are performed, from the case of the infant where the mere prick of a pin will raise the pulse twenty or thirty beats, to that state of torpitude in old age in which burning and gangrene cause little sensation. Probably the task impressed upon the vital power is to harden the tissues, especially the nerves, with advancing age, so that they will fulfil their office with more and more toil till at last the vital power cannot traverse them sufficiently to impel them to their actions, and life ceases. We see then that death is in all respects a widely different process from sleep though it has been so favourite an image of the poet's to paint them as twins, and that it is always one and the same result from a similar mode of action, performed by the same agency and ensuing under the same law as exercise and digestion; namely, the passing of the vital power to any part of the frame touched by an agent having a particular affinity for the vital power.

But it is now time to examine the view generally entertained respecting what is more usually known as disorder and disease, and to this I purpose giving up a separate chapter or two.

CHAPTER X.

LIFE IN THE BLOOD.

"What a thousand years since would not to a rational man, contemporary with the first voucher, have appeared at all probable, is now urged as certain and beyond all question, only because several have since, from him, said it one after another."-LOCKE.

In this chapter I set out with the supposition that every person living has a theory for any disease under which he may happen to suffer, at least I never recollect to have met with any one who could not explain. the pathology of his malady to his entire satisfaction. Either "its in the blood," or "on the nerves," or "its got into the constitution."

But it is particularly on the state of the blood that every person comes out so strong. He (every person) may suppose "its on the nerves" when he has got fits or low spirits, but no sooner does he espy a crop of boils or an outbreak of spots, than anything like hesitation vanishes and he at once rushes pleno rivo to the conclusion that "its in the blood," which of course must be purified. On being asked how he knows that "its in the blood," he can only say that it must be there or in "the humours." Tell him that what he calls humours are simply excretions or secretions, which being expelled from the circulating system previous to being discharged in great part from the frame, can have no influence good or bad, and he retorts, "then where is it if it's not in the blood?"