VII. OF HABIT. 



It is easier to teel the meaning of this term than to define it. Habit, 

 however, may be said to consist in the frequent repetition of certain acts, 

 or certain motions, in which the whole body participates, or only some 

 of its'parts. The most remarkable effect of habit, is to weaken after a 

 time the sensibility of organs. Thus, a catheter introduced along the 

 urethra, and allowed to remain there, causes during the first day, rather 

 sharp pain, on the second day, it feels less uneasy ; on the third day it is 

 only troublesome; and on the fourth, the patient scarcely feels it. The 

 use of snuff at first increases the secretion of mucus in the nose, but 

 if continued a certain time, it ceases to affect the pituitary membrane, 

 and the secretion would diminish considerably but for the practice of in- 

 creasing daily the quantity of that acrid powder; the presence of a ca- 

 nula in thenasalduct, after the operation for fistula lachrymalis, increases 

 at first the mucous secretion of that canal ; but in proportion as it 

 becomes accustomed to the extraneous body, the secretion returns to its 

 natural condition. 



It is only by our sensations that we are aware of our existence. Life, 

 to make use of the figurative language of system, of a modern writer, 

 consists in the action of stimuli on the vital powers. (Tola vita, quanta 

 est, consistit in stimulo, et vi vitali. Brown.) Sentient beings feel a conti- 



ofthe more intimate consent which exists between parts, we are not accurately in- 

 formed. Those sympathies which prevail among the various viscera of the abdomen, 

 and between them and the head, neck and contents of the thorax, may, perhaps, 

 be explained by the extensive anastomoses of the intercostals with almost all the 

 nerves which proceed from the spinal marrow. But there are many other sympa- 

 thies, equally conspicuous, between parts, the nerves of which (apparently)* have 

 not the slightest connexion. Here it appears that, either by the co-operation of 

 different organs in the performance of a function, as in the complex apparatus sub- 

 servient to respiration, or from similarity of structure, parts, though detached, be- 

 ing prone to be affected by the same cause, as the parotid glands and testes in the 

 7nale, and the same gland with the mammae in the female, the habit of acting in unison 

 is acquired, and sometimes confirmed. This habit of concerted action is called associ- 

 ation, and has been adopted as a principle by Locke, by Hartley, and by Darwin, to ac- 

 count for the connexion which is discernable in many of the motions of the body, as well 

 as in the operations of the mind. Both the sound and morbid states of the system pre- 

 sent numerous instances of these associated actions, some of which are constant and 

 uniform, while others are occasional, and anamolous, produced as it were accident- 

 ally. 



The principle of sympathy extends throughout the body, every portion of it being 

 susceptible of associative actions, by which means the different parts are linked toge- 

 ther so as to form one whole. Certain organs however, are more eminently endowed 

 with the property, as the uterus, the brain, and especially the stomach. This last vis- 

 cus constitutes the chief medium of sympathetic connexion. With it, the brain, thtf 

 organs of sense, and deglutition, the whole of the thoracic and abdominal viscera; 

 the parts of generation in each sex, the blood vessels, the joints, the exterior surface, 

 and in short all the parts of the system however minute, maintain a close and intimate 

 sympathy. Placed in the middle, the stomach is the centre of the greatest sphere of 

 sympathy. But, besides this great sphere, there are many subordinate ones, which our 



narrow limits will not permit us particularly to designate : as for example, the uterus, 

 with the different portions of its own system, the ovaries, the mammae, &c. &c. It was 



on account of its vast dominio " x **-*'<* -*^~- *- v 



Helmont selected the stomac 

 Stahl and Mcholte Chapmai 



on account of its vast dominion over the system, by its multiplied sympathies, that Van 

 Helmont selected the stomach as the residence of his archxuz, the anima medica } of 



