INTRODUCTION.
THE study of Medicine may be shortly stated to consist in the investigation of the means whereby disease is prevented, alleviated, or cured. By disease is to be understood an altered condition of the fluid or solid constituents of the body, in consequence of which the whole of its functions, or some one or more of them, are deranged. It must, however, be borne in mind that, within certain limits, the function of an organ may be increased or diminished, without the confines of health being passed; nor should it be forgotten, on the other hand, that considerable alteration of the structure of an organ is compatible with the apparently healthy performance of its function. In forming an idea of disease, we must, therefore, keep in view such derangement of function as is subversive of health and comfort, and such alteration of structure as is calculated, if it should not be removed, ultimately to produce it.
Viewed in this way, diseased conditions are not always to be regarded as something superadded to the system as entities, so to speak, but rather as the performance of the natural functions under circumstances which are foreign or abnormal. For example, the violent muscular contractions which occur in an attack of Epilepsy, due to the presence of worms in the intestinal canal, are but the normal or natural actions of muscular tissue, under the influence of an excessive stimulus. So, likewise, the heat of skin and the profuse sweating that are present during a paroxysm of ague, merely represent the healthy reaction of the system, which is the necessary result of the presence of a poison in the blood. It is plain therefore that, in many diseased states, it would be in the highest degree irrational to attempt to put a stop
