34 PHILOSOPHY OF ZOOLOGY. 



commencement of life, and to the exercise of its func- 

 tions, let us now attend to some of the phenomena present- 

 ed by organized bodies during the continuance thereof. 

 When all the organs are in such a degree of perfection as 

 to be able, easily and durably, to perform the functions of 

 life, the body is said to be in a state of Health. The an- 

 cients recognized a Goddess, who was supposed to preside 

 over this condition, whom the Greeks termed 'Yy<s<*, and the 

 Romans Salus. 



When we consider the situation in. which organized bo- 

 dies are placed on the surface of the globe, the changes 

 which take place in the quantity and nature of their food, 

 the variations in the temperature of the surrounding ele- 

 ments, besides the occurrence of an infinite variety of acci- 

 dents, all calculated to retard or derange their motions, 

 we may expect to find many individuals, in which the har- 

 mony between the different parts is interrupted, and the 

 functions of particular organs suspended, producing a con- 

 dition the opposite of health, termed Disease. The unin- 

 terrupted influence, indeed, of external objects, acting 

 either directly or indirectly, precludes the possibility of an 

 organized body enjoying perfect health for any length of 

 time. These obstacles, however, are in part removed, by 

 the power which each individual possesses of accommoda- 

 ting itself to circumstances ; of varying, within a certain 

 range, its form, structure, and actions ; of repairing inju- 

 ries ; and of continuing to live, though in part mutilated. 

 Such displays of the vital power are familiar to the Phy- 

 sician, and constitute the very basis of the healing art. 



Besides the destructive influence of external objects, we 

 may refer many of the diseases which assail organized bo- 

 dies, to some imperfection or derangement of the vital 

 principle itself. This is obviously the case, when a*i organ 



