20 GENERAL VIEW OF THE FUNCTIONS. 



The ancients arranged all these functions in four classes : 

 The vital, or those constantly necessary to life, comprising respir- 

 ation and the action of the heart : the natural, or those by which 

 the body is nourished: the animal, or those which principally 

 distinguish animals from vegetables, viz. sense, consciousness, 

 desires, thought, volition : and the genital. 



The functions are now generally arranged in two classes : the 

 animal, constituting one peculiar to animals ; and the vital and 

 natural, united into another, common to vegetables and animals, 

 under the title of organic or vital. The generative, relating in 

 their object to the species rather than to the individual, and of 

 but temporary duration, are thrown into a separate and inferior 

 division, but in fact, except the animal passion, are part of the 

 organic. 



We owe the revival of this classification, and our knowledge of 

 the characteristics of each class of functions, to Dr. Wilson Philip a 

 and Xavier Bichat b ~; although the latter, from having published a 

 work expressly on the subject, has received the whole honour, 

 both in Great Britain and on the Continent. 



The animal functions prove us feeling, thinking, and willing 

 beings : they are the actions of the senses which receive impres- 

 sions ; of the brain which perceives them, is conscious, desires, 

 reflects, and wills ; of the voluntary muscles which execute the 

 will in regard to motion; and of the nerves which are the agents 

 of transmission : the brain is their central organ. The vital or 

 organic functions are independent of mind, and give us simply 

 the notion of life : they are digestion, circulation, respiration, 

 exhalation, absorption, secretion, nutrition, calorification : the 

 heart is their central organ. 



The organs of the animal functions are double and correspon- 

 dent, there being on each side of the median line of the body 

 either two distinct organs, as the eyes, ears, extremities ; or two 

 correspondent halves, as is the case with the brain, spinal marrow, 

 nose, tongue, &c. 



a Treatise on Febrile Diseases, ch. iii. sect. 3. First edition. 1799. Paper 

 read to the Royal Med. Society of Edinburgh, 1791 or 1792, and inserted in its 

 Records. Essay on Opium. 1795. Edinburgh Med. and Surgical Journal, 

 July, 1809. p. 301. sq. 



b Recherches Physiologiques surla Vie et la Mort. 1805. 



