232 ANIMAL FORCES. [ii. 



place (137, iv) ; and thus, althougli its direct nerve-actions con- 

 tinue, the indirect no longer occur (428, vi). 



V. Lastly, in consequence of this frequent repetition of an 

 external impression, the reflexion ' and transformation may- 

 take place so imperfectly, that it is not transmitted as a non- 

 conceptional internal impression, with sufficient force to reach 

 the accustomed mechanical machines (138) ; and thus the 

 indirect nerve-actions cease, although the ordinary direct 

 actions, or other direct actions still occur (429) 



431. That continued-frequent repetition, or habit , has con- 

 siderable influence on nerve-actions excited by external im- 

 pressions, as well as on external sensations and their actions, 

 is proved not only by the analogy of all experience as regards 

 the latter (51), but also by experience in all instances in which 

 the external impression is not felt. The habituation to various 

 foods, poisons, &c., are examples of this kind. The movements 

 excited by these, until a person is habituated to them, are 

 usually nerve-actions of their external impressions, and con- 

 tinue to be such, although they may be felt (364, ii) ; but these 

 movements often cease from constant repetition of the stimulus. 



432. The organisms of those animals, whose organs beiag 

 well supplied with nerves, have, as compared with other 

 animals, a vivid sensibility (417), are termed irritable organisms 

 (animals) : those which are the contrary, are inirritable. Sen- 

 sibility [empfindlichkeit] may co-exist with irritability, and 

 insensibility with inirritability ; but irritability does not always 

 imply sensibility, because a very irritable organ, as the heart 

 or stomach, may be endowed with a less sensibility than a less 

 irritable one, as the tongue. But as sensibility implies irrita- 

 bility, the latter enters also into the temperament^ or corporeal 

 constitution (52), and like the former, is influenced by habit, 

 and thus forms the basis of all the peculiarities of idiosyncrasy 

 (Haller ^Elem. Phys/ tom. iv, p. 576). 



Note. — That which Haller terms vis insita [angeborne 

 Kraft], is really only a part of the same property of animal 

 organisms, and has the same relations to sensibility and habit ; 

 for, according to our views, it is nothing else than the vis 

 nervosa of external impressions exciting direct nerve-actions. 

 Let the reader compare Mailer's ^ Physiology,' § 400, with 

 other parts of his works, and with our own views, and it will 



