SECT. XXXII. 5. DISEASES OF IRRITATION. 429 



Simulated into acYion by the peculiar pungency of 

 the fluids they abforb, fo in the inteilinal canal the., 

 pungency of the digefting aliment, or the acrimony 

 of the faeces, ieein to contribute, as well as their 

 bulk, to promote the periftaltic motions ; and in the 

 arterial fyftem, the momentum of the particles of 

 the circulating blood, and their. acrimony, ftimulate 

 the arteries, a$ well as the diftenUon occafioned 

 by. it. ., Where the pulfe is fmall this defeci of dif- 

 tentiott is prefent, and. contributes much, tQ pro- 

 duce the febris irritativa pulfu debili, or irritative 

 fever with weak pulfe, called by modern writers 

 nervoits fever,, as a predifponent caufe. See Sec"t. 

 XII. I. 4. Might not the transfufion of blood, 

 fuppoie of four ounces daily from a ftrong man, 

 or other healthful animal, as a fheep or an afs, be 

 ufed in the early ftate of nervous or putrid fevers 

 with great profpcl of fuccefs ? 



V. The defed of the momentum of the particles 

 of. the circulating blood is another caufe of the 

 quiefcence., . with which the cold fits of fever com- 

 mence. This ftimulus of the mpmentuin of the pro- 

 greflive particles of the blood docs not aft over 

 the whole body like thofe of heat and diflention 

 above defcribed; but is confined to the arterial fyf- 

 tern ; an'd differs from, the ftimulus of the detention 

 of the bloody as much as the vibration of the air 

 does from the currents of it. Thus are the dif- 

 ferent organs of our bodies ftimulated by four dif- 

 ferent mechanic properties of the exteirial world : 

 the fenfe of touch by the predu.re of folid bodies 

 fc> as to diftinguifh their figure; the mufcular fyf- 

 tem by the diftention, which they . occaiion ; the 

 internal furface of the arteries, by the .momentum 

 of their moving particles; and the auditory nerves, 

 by the vibration of them : and thefe four mechanic 

 properties are as different from each, other as the 

 F f % various 



