394 DISEASES CLASS IV. 1.3.3, 



the thread by a {licking plafter to a diftant part. An iflue be- 

 hind the ear. To praclife daily by a looking-glafs to ftop the 

 motions with the hand. See the cure of a cafe of the leaping of 

 a mufcle of the arm, Sec~l. XVII. i. 8. See Convulfio debi* 

 lis, Clafs III. i. i. 5. Frequent eleclric fparks, or very flight 

 (hocks. . 



3. Rifus invitus. Involuntary laughter. When the pleafure 

 ariftng from new combinations of words and ideas, as in puns ; 

 or of other circumftances, which are fo trivial, as to induce no 

 voluntary exertion to compare or confider their prefent impor- 

 tance or their future confeqiience ; the pleafure is liable to rife 

 into pain 5 that is, the ideas or fenfual motions become exerted 

 too violently for want of fome antithefiftic ideas ; in the fame 

 manner as thofe mufcles, which have weak antagonifts,as thpfe of 

 the calf of the leg, are liable to fall into cramp or painful contrac- 

 tion. In this fituation a fcream is begun to relieve this pain of 

 ideas too violently exerted, which is ftopped again foon, as ex- 

 plained in Sea. XXXIV. i. 4. and Clafs III. i. i. 4. and IV. 



2. 3. 3. 



The pain, into which this pleafure rifes, which would excite 

 the fcream of laughter, has been felt forcibly by every one ; 

 when they have been under fuch circumftances, as have induc- 

 ed them to reftrain it by a counter-volition ; till at length the 

 increafed affociate motions produce fo much pain as to over- 

 come the counter-volition, and the patient burfls out into inde- 

 cent laughter, contrary to his will in the common acceptation of 

 that word. 



4. Litfus digitorum invitus. An awkward, playing with the 

 fingers in fpeaking in public. Thefe habits are begun through 

 bamfulnefs, and feem rather at fir ft defigned to engage the at- 

 tention in part, and thus prevent the difagreeable ideas of mau* 

 vaife honte ; as timorous boys whiftle, when they are obliged to 

 walk in the dark ; and as it is fometimes neceflary to employ 

 raw foldiers in perpetual manoeuvres, as they advance to the 

 firft charge. 



5. Unguium morjiuncula invita. Biting the nails is a de- 

 praved habit arifing from fimilar caufes as thofe of the laft arti- 

 cle. 



M. M. Dip the fingers in folutiori of aloes. 



6. Vigilia invita. Watchfulnefs, where the perfon wifhes 

 and endeavours to fall afleep, properly belongs to this place, as 

 the wifh or volition to fleep prevents the defired effect ; be- 

 caufe fleep confifts in an abolition of volition. See Clafs III. 



I. 2. 3. 



ORDO 



