60 



diseases, or of rendering them more supportable; medicine, in ail its 

 parts, is enlightened by physiology, and cannot have a surer guide. Ow- 

 ing to a neglect of this auspicious guide, therapeutics and materia medica 

 long remained involved in a mist of conjectures and hypotheses. Physi- 

 cians should never for a moment forget, that as'a great number* of dis- 

 eases consist in a derangement oi the vital function, all their efforts 

 should tend to bring back sensibility and contractility to their natural con- 

 dition : that the best classification of diseases and of medicines, is that 

 which is founded on a judicious distinction of the vital powers. With 

 this view it is that M. Alibert, in his elements of materia medica, classes 

 medicines according to their effects on sensibility or contractility, and 

 according to the organs on which their action is particularly exerted. 



XII. CLASSIFICATION OF THE VITAL FUNCTIONS. 



After having treated separately of the vital powers or faculties, nothing 

 is easier than to arrange, in a clear and methodical order, the functions 

 carried on by the organs which these powers call into action. The term 

 function^ might be defined, means of existence. This definition would be the 

 more just as life is only the exercise of these functions, and as in cases, 

 when any one of the more important can no longer be carried on. From 

 not distinguishing the faculties from the functions which are merely the 

 acts of faculties or powers, several modern divisions, though far prefera- 

 ble to the old classification of the functions into vital, animal, and natural, 

 are, nevertheless, deficient in accuracy and simplicity. Thus Vicq-d'Azyr, 

 in the classification of the phenomena of physiology inserted in the dis- 

 course which he has prefixed to his work on anatomy, mistakes the 

 cause for the effect, and places sensibility and irritability among the 

 functions, and commits another mistake, by ranking among the latter, os- 

 sification, which is but apeculiar mode of nutrition, belonging to parts of 

 a hard structure. 



The best method of classing the actions which are performed in 

 the living human body is doubtless, that by which they are distributed 

 and arranged according to the object which they fulfil. Aristotle, Buf- 

 fon, and especially Grimaud, have laid on that base the foundation of a 

 method which we shall adopt, with the modifications which we are about 

 to mention. 



Aristotle and Buffon had observed, that among the acts of the living 

 oeconomy, some were common to all beings that have life, to plants and 

 animals during sleep and in waking, while others seemed to belong ex- 

 clusively to man, and to the animals which more or less resemble him. 

 Of these two modes of existence, the one vegetative, the other animal, 

 the former appeared to them the more essential, as being more diffused, 



* All diseases consist in physical derangements, as solutions of continuity, displace- 

 ments, organic alterations, as polypi, aneurisms, and other affections resulting from or- 

 ganic affection and alteration of structure ; vital lesions, as fevers, ataxite, adynamise, 

 vesanise, &c. see Nosographie Chirnrgicale. Jluthor's^'ote. 



f The function of any part, is the office or duty it fulfills, or the end for which it is 

 designed. The function of the lachrymal gland is to secrete tears: of the ducts, to 

 convey them to the nose, &c. Life must exist anterior to the performance of function, 

 although the correct discharge of the latter is necessary to the continuance of the former. 

 The definition, as applied to the term function, is incorrectwhen it refers to the re- 

 sults produced by function, it is unexceptionable. Godman. 



