448 BIOLOGY. 



action be wholly withdrawn, then the secretion will be- 

 come less. 



2719. The more irritable the nerves are, by so 

 much the more animal does the vegetable organism, or 

 the splanchnic system, therefore become ; so much the 

 less is it produced on the mass. 



2720. Irritable animals and men are therefore meagre 

 or lean. The two cases are uniformly related to each 

 other. Lean men are irritable, not perhaps because the 

 nervous ends are not covered with fat, such as there 

 might be over the integument, the ear, the tongue, 

 nose, &c., but, because where the nutritive process is 

 inactive, what is animal necessarily preponderates. There 

 are consequently three kinds of nervous actions, or 

 phenomena, though all nervous activity in entire systems 

 is similar, or but one. The difference is only derived 

 from the organ upon which the nerves act. There are, 

 consequently, no special nerves of sensation, motion and 

 secretion ; or such, forsooth, as have only one of these 

 offices to take care of. Thus, were a nerve of sensation 

 to be prolonged or drawn over a muscle, it would excite 

 motion, and in the case of the liver, secrete bile, &c. 



Mesmerism. 



2721. When the sensibility mounts to the highest 

 degree, each mass-function will then almost cease, and 

 the organs of sense feel the weakest operation of the 

 stimulus. 



2722. Since every stimulation is a polarizing act, and 

 each body is in polar activity towards the other at every 

 conceivable distance, so may an extremely irritable ner- 

 vous system also perceive the feeblest polarizations. 



2723. The eye perceives the polarization at a remote 

 distance from the body whence it proceeds. 



2724. In hearing the vibrating body still indeed 

 acts directly upon the ear through the vibrations of air. 

 But a finer, i. e. more irritable ear, hears farther than 

 one that is more dull. 



2725. With an elevated sensibility the other systems 



