DISEASES CLASS III. 1.1.19. 



it, arifes from excels of volition, and not from a fufpenfion of it ; 

 and though, like other kinds of epilepfy, it often attacks the pa- 

 tients in their fieep, yet thofe two, whom I faw, were more fre- 

 quently feized with it while awake, the fleep-walking being a 

 part of the reverie. See Sett. XIX. and XXXIV. 3. and Clafs 



II. I. 7. 4. and III. I. 2. 1 8. 



M. M. Opium in large dofes before the expected paroxyfm. 



10. AJlhma convulflvum. The fits of convulfive afthma return 

 at periods, and are attended with cold extremities, and fo far 

 refemble the accefs of an intermittent fever ; but, as the lungs 

 are not fenfible to the pain of cold, a fhivering does not fuc- 

 ceed, but inftead of it violent efforts of refpiration ; which have 

 no tendency, as in the humoral afthma, to diflodge any offend- 

 ing material, but only to relieve the pain by exertion, like the 

 (huddering in the beginning of ague-fits, as explained Clafc. 



III. I. I. 2. 



The infenfibility of the lungs to cold is obfervable on going 

 into frofty air from a warm room j the hands and face become 

 painfully cold, but no fuch fenfation is excited in the lungs ; 

 which is another argument in favour of the exiftence of a peculiar 

 fet of nerves for the purpofe of perceiving the univerfal fluid 

 matter of heat, in which all things are immerfed. See Sect. 

 XIV. 6. Yet are the lungs neverthelefs very fenfible to the de- 

 ficiency of oxygen in the atmofphere, as all people experience, 

 when they go into a room crowded with company and candles, 

 and complain, that it is fo clofe, they can fcarcely breathe ; and 

 the fame in fome hot days in fummer. 



There are two difeafes, which bear the name of afthma. The 

 firft is the torpor or inability of the minute vefTels of the lungs, 

 confifting of the terminations of the pulmonary and bronchial 

 arteries and veins, and their attendant lymphatics ; in this cir- 

 cumftance it refembles the difficulty of breathing, which attends 

 cold bathing. If this continues long, a congeftion of fluid in 

 the air-cells fucceeds, as the abforbent actions ceafe completely 

 before the fecerning ones ; as explained in Clafs I. i. 2. 3. 

 And the coldnefs, which attends the inaction of thefe vefiels, 

 prevents the ufual quantity of exhalation* Some fits ceafe be- 

 fore this congeftion takes place, and in them no violent Tweet- 

 ing nor any expuition of phlegm occurs. This is the humoral 

 afthma, deicribed at Clafs II. i. I. 7. 



The fecond kind of afthma confifts in the convulfive actions 

 in conference of the difagreeable fenfations thus induced ; 

 which in fome fits of afthma are very great, as appears in the 

 violent efforts to raife the ribs, and to deprefs the diaphragm, 

 by lifting the (houlders. Thefe, fo long as they contribute to 



remove 



