14 PRINCIPLES OF PHYSIOLOGY. 



other machines, which by their union communicate equally 

 compound forces to the general machine. On the other hand, in 

 the artistic machines, the coarser elements are either not me- 

 chanical machines at all, but only mere physical bodies, or else 

 impart to the whole machinery no other mechanical forces than 

 those which they would still have, if their constituent elements 

 were not machines. The nature of the organic machines, con- 

 sidered as such only, is termed their organic nature, and the 

 continuance of organic nature is organic life, which is common 

 to anim^als and vegetables. 



6. Organic (or natural) machines are termed animal ma- 

 chines when, in addition to their physical composition, organical 

 structure, and the general forces of physical and mechanical 

 bodies, they are endowed with other forces, which do not regu- 

 late such bodies and machines, according to the general laws of 

 motion, but are only adapted to them by means of an arrange- 

 ment, the nature of which is unknown. These forces are termed 

 (primary) animal forces ; and the movements directly produced 

 by them are (primary) animal movements. When animal ma- 

 chines are combined with those that are purely mechanical, and 

 the latter are moved by the animal forces of the former, they 

 possess communicated animal forces, and by means of these the}^ 

 also perform animal movements. The aggregate of the animal 

 forces in the body of an animal is termed its animal nature. 

 The animal nature of a body depends on the peculiar condition 

 of the materials of which the animal machines, as such, consist ; 

 on the structure of the animal machines ; on the animal forces 

 themselves; and on the connection of the animal with the other 

 organic machines of the organism, whereby the forces and 

 movements of the latter are stamped with the animal character. 

 The continuance of animal nature is animal life, and its termi- 

 nation animal death. In all living animals the animal forces 

 act either in perfect accord with the sentient force of the mind, 

 or not : if the former, then a distinct class of animal movements 

 in the body is connected with each class of ideas, and conse- 

 quently both reciprocally contain the basis of their twofold ex- 

 istence. These united animal and sentient forces are termed 

 animal-sentient forces; and the movements they produce are 

 sentient actions (actiones animse). When the animal forces act 

 independently of the sentient force, they are termed pure animal 



