which, in the aggregate, constitute the visible changes and actions which we say characterize life. The anatomist has never discovered any "central point," nor the microscopist any "single cell," which governs the motions of the rest. Every supposed "central point" has been found, on microscopic examination, to split up into innumerable millions of centres, or individual cells. Moreover, in plants, in which the processes of life appear to be directed quite as intelligently as they do in animals, no trace of a nervous system has yet been demonstrated.
To many of my readers it would perhaps be a much more acceptable explanation of the (what seem to be) intelligently-directed processes going on in living bodies, than either of those already mentioned, to say that they must be ascribed to the rational will of a Creator urging an unconscious organism, by the laws he has ordained, to perform certain acts necessary to its preservation.
But, as the absolute scientists and those who religiously believe in a Creator are just now crossing swords, I will not press this third explanation, but rather choose to sustain the position I have assumed on the broader middle ground of natural philosophy.
To return, therefore, to the main proposition, namely, that organic diseases are naturally designed for, and do in fact accomplish, the prolongation of life, it will be observed that I have purposely omitted from consideration those other and more simple kinds of derangement which we call functional diseases. The conservative use of many of these latter has been universally recognized. The vomiting that occurs when poisons or indigestible matters have been introduced into the stomach, does good, by removing the offending substances. In like manner, the functional derangement of cough secures the expulsion of irritating gases or powders that have been inhaled, and of the accumulations of mucus that occur in every bronchial catarrh, and which would otherwise clog the tubes and induce suffocation. The watery diarrhœas that arise from indigestible articles having passed into the intestine, cure themselves by washing away the irritating materials, and the intelligent physician, instead of curbing the derangement, assists it with a laxative, and so helps Nature with the cure.
When, however, we come to speak of the more permanent structural changes, which neither Nature nor art can remove, and which have seemed to produce premature death, scarcely any one will acknowledge that the processes which develop them are at all conservative. Yet they are. And the error of supposing they are not has arisen chiefly from a total misunderstanding as to the nature of disease. A very prevalent idea, if not indeed a universal one, seems to be, that disease is a separately-existing entity—a thing independent of the body and inimical to it. We constantly hear, for example, of an individual being "attacked" with pneumonia; of an army "as-
