THE EXCITING CAUSE 215 



is subsequently made good by new and closely similar combinations 

 as a result of continued movements, whereas in the unorganised or 

 disorganised fermenting body, the decompositions which occur cannot 

 be made good by a continuance of fermentation. 



As soon as an individual dies, its body, which is then disorganised 

 in reality though often not in appearance, immediately joins the class 

 of bodies liable to fermentation, particularly as regards the more 

 supple of its parts. The exciting cause which gave it life then hastens 

 the decomposition of such of its parts as are capable of fermentation. 



We learn then from the principles set forth above that the exciting 

 cause of vital movements must necessarily be sought in the invisible, 

 subtle, penetrating and ever active fluids with which the environment 

 is always supplied ; and that the chief element of this cause is the 

 element which maintains an orgasm essential to the existence of life, 

 and, in fact, that it is no other than caloric ; as the following 

 observations will further bring out. 



I need not cite any special instances on this subject, since the general 

 fact concerned is well known. We are aware that a certain quantity 

 of heat is generally necessary to all hving bodies and especially animals. 

 When it is reduced below a certain point, the irritabihty of animals 

 becomes less intense, their organisation less active and all their 

 functions flag or are performed slowly, especially in those animals 

 where there is no production of internal caloric. When it becomes 

 still further reduced, the most imperfect animals die and a great 

 many of the rest fall into a torpid lethargy and undergo a suspension 

 of life ; it cannot be doubted that they would in turn all lose their 

 lives, if this reduction of heat were to be carried much further in the 

 environment. 



When the temperature rises, on the contrary — that is, when the heat 

 increases and is distributed everywhere— we constantly notice, if this 

 state of things continues, that life revives and seems to acquire new 

 strength in all Uving bodies, that the irritability of the internal parts 

 of animals rises proportionally in intensity, that the organic functions 

 are carried on with more energy and promptitude, that the various 

 stages of life succeed each other with greater rapidity, and that life 

 itself comes sooner to an end, but that the new generations are more 

 frequent and abundant. 



Although heat is everywhere necessary for the maintenance of Ufe 

 especially in animals, its intensity should not much exceed certain 

 limits ; for if it did animals would suffer greatly from it, and in the 

 case of the highly complex would be exposed at the slightest cause to 

 rapid diseases, which would quickly result in death. 



We may then be sure that not only is heat necessary to all living 



