342 DISEASES CLASS III. 2. 1. 13. 



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

 insanity. In its still more powerful degree, the superabundance 

 of this sensorial power actuates and invigorates the whole moving 

 system, giving strength and frequency to the pulse, and an uni- 

 versal glow both of colour and of heat, as in violent anger, or out- 

 rageous insanities. 



If, in the feverish sleep above described, the skin becomes 

 cooled by the evaporation of much perspirable matter, or by the 

 application of cooler air, or thinner clothes, the actions of the 

 cutaneous capillaries are lessened by defect of the stimulus of 

 heat, which counteracts the increase of sensibility during sleep ? 

 and the pulsations of the heart and arteries become slower from 

 the lessened stimulus of the particles of blood thus cooled in the 

 cutaneous and pulmonary vessels. Hence the admission of cold 

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

 hot skin, whether they be attended with arterial strength, or ar- 

 terial debility, renders the pulse slower; in the former case by 

 diminishing the stimulus of the blood, and in the latter by less- 

 ening the expenditure of sensorial power. See Suppl. I. 8. 

 and 15. 



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

 the desire of locomotion is vehement, but the muscles do not 

 obey the will; it is attended with great uneasiness, a sense of 

 suffocation, and frequently with fear. It is caused by violent 

 fatigue, or drunkenness, or indigestible food, or lying on the back, 

 or perhaps from many other kinds of uneasiness in our sleep, 

 which may originate either from the body or mind. 



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

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

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

 during sleep, when the voluntary power is suspended. Whence 

 the blood may accumulate in them, and a painful oppression su- 

 pervene; as in some haemorrhages of the lungs, which occur dur- 

 ing sleep; and in patients much debilitated by fevers. See Som- 

 nus interruptus, Class I. 2. 1. 3. and 1. 2. 1.9. 



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

 well informed by one patient, always produced this disease in 

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

 system is much decreased by fatigue, as it exhausts the sensorial 

 power; and secondly, too much wine and stimulating food will 

 again diminish the irritability of some parts of the system, by em- 

 ploying a part of the sensorial power, which is already too small, 

 in digesting a great quantity of aliment; and in increasing the 

 motions of the organs of sense in consequence of some de- 



