1 62 THE POPULAR SCIENCE MONTHLY, 



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 innumer- 

 able 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 demon- 

 strated. 



To many of my readers it would perhaps be a much more accept- 

 able explanation of the (what seem to be) inteIlir/entli/-diYected pro- 

 cesses going on in living bodies, than either of those already men- 

 tioned, to say that they must be ascribed to the rational will of a 

 Creator iirging 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 oc- 

 curs 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 expul- 

 sion 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 diarrhoeas 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 de- 

 rangement, assists it with a laxative, and so helps Nature with the 

 cure. 



When, however, we come to speak of the more permanent struct- 

 ural changes, which neither Nature nor art can remove, and which 

 have seemed to produce premature death, scarcely any one will ac- 

 knowledge that the processes which develop them are at all conserva- 

 tive. Yet they are. And the error of supposing they are not has 

 arisen chiefly from a total misunderstanding as to the 7iature of dis- 

 ease. 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- 



