342 DISEASES Class III. 2. i. 13. 



minifhes or deflroys fenfations and irritations, which are ftrongei* 

 than natural, as in intoxication, or which precede convulfions, 

 or infanity. In its ftill more powerful degree, the fuperabun- 

 dance of this fenforial power actuates and invigorates the whole 

 moving .fyftern, giving ftrength and frequency to the pulfe, and 

 an univerfal glow both of colour and of heat, as in violent an- 

 ger, or outrageous infanities. 



If, in the feverifh fleep above defcribed, the fkin becomes cool- 

 ed by the evaporation of much perfpirable matter, or by the ap- 

 plication of cooler air, or thinner clothes, the actions of the cu- 

 taneous capillaries are leffened by defect: of the ftimulus of heat, 

 which counteracts the increafe of fenfibility during fleep, and 

 the pulfations of the heart and arteries become flower from the 

 leflened ftimulus of the particles of blood thus cooled in the cu- 

 taneous and pulmonary vefiels. Hence the admiffion of cold 

 air, or ablution with fubtepid or with cold water, in fevers with 

 hot fkin, whether they be attended with arterial ftrength, or ar- 

 terial debility, renders the pulfe flower j in the former cafe by 

 diminifhing the ftimulus of the blood, and in the latter by lef- 

 fening the expenditure of fenforial power. See Suppl. I. 8. 

 and 15. 



13. Incubus. The night-mare is an imperfect ileep, where 

 the defire of locomotion is vehement, but the mufcles do not 

 obey the will ; it is attended with great uneafinefs, a fenfe of 

 fuffocation, and frequently with fear. It is caufed by violent 

 fatigue, or drunkennefs, or indigeftible food, or lying on the 

 back, or perhaps from many other kinds of uneafinefs in our 

 ileep, which may originate either from the body or mind. 



Now as the action of refpiration is partly voluntary, this com- 

 plaint may be owing to the irritability of the fyftern being too 

 fmali to carry on the circulation of the blood through the lungs 

 during fleep, when the voluntary power is fufpended. Whence 

 the blood may accumulate in them, and a painful opprefhon fu- 

 pervene ; as in fome haemorrhages of the lungs, which occur 

 during fleep ; and in patients much debilitated by fevers. See 

 Somnus interruptus, Clafs I. 2. 1.3. and I. 2. 1. 9. 



Great fatigue with a full fupper and much wine, I have been 

 well informed by one patient, always produced this difeafe in 

 himfelf to a great degree. Now the general irritability of the 

 fyftern is much decreafed by fatigue, as it exhaufts tne fenforial 

 power ; and fecondly, too much wine and ftimulating food will 

 again diminifh the irritability of fome parts of the fyftern, by 

 employing a part of the fenforial power, which is already too 

 fmall 9 in digeiting a great quantity of aliment -, and in increafing 

 the motions of the organs of fenie in confequence of fome de~ 



