CLASS III. 2. i. 1 1. OF VOLITION. 339 



ly publifhed fome fucccfsful cafes of the ufe of mercurial oint- 

 ment. See Colica Saturnina, I. 2. 4. 8. See Clafe III. 2. i. 4. 

 Dr. J. Alderfon has lately much recommended the leaves of 

 rhus toxicodendron (fumach), from i. gr. to iv. of the dried 

 powder to be taken three or four times a day. Eflay on Rhus 

 Toxic. Johnfon, Londctfi, 1793. But it is difficult to know 

 what medicine is of fcrvice, as the movements of the mufcles 

 mult again be learned, as in infancy, by frequent efforts. 



11. Paraplegia. A palfy of the lower half of the body di- 

 vided horizontally. Animals may be conceived to have double 

 bodies, one half in general refembling fo exactly the other, and 

 being fupplied with feparate fets of nerves , this gives rife to 

 hemiplegia, or palfy of one half of the body divided vertically ; 

 but the paraplegia, or palfy of the lower parts of the fyftem, 

 depends on an injury of the fpinal marrow, or that part of the 

 bruin which is contained in the vertebrae of the back ; by which 

 ail the nerves fituated below the injured part are deprived of 

 their nutriment, or precluded from doing their proper offices ; 

 and the mufcles, to which they are derived, are in confequence 

 difobediem to the power of volition. 



This fometimes occurs from an external injury, as a fall from 

 an eminence ; of which I faw a deplorable initance, where the 

 bladder and recium, as well as the lower limbs, were deprived 

 of fo much of their powers of motion, as depended on volition 

 or fenfation ; but I fuppofe not of that part of it, which dep. 

 on irritation. In the fame manner as the voluntary mufcles in 

 hemiplegia are fometimes brought into action by irritation, as 

 in ftretching or pandiculation, deicribed in Sect. VII, i. 3. 



But the moil frequent caufe of paraplegia is from a protuber- 

 of one of the fpinal vertebrae ; which is owing to the in- 

 nutrition or foftnefs of bones, defcribed in Clafs I. 2. 2. 17. 

 The cure of this deplorable diieafe is frequently efffcfed by the 

 ilimulus of an iffue placed on each fide of the prominent foine, 

 as ririb pubiilhed by Mr. Pott. The other means recommend- 

 ed in foftnefs of bones ihould alto be attended to ; both in re- 

 fpect to the internal medicines, and to rhe mechanical methods 

 of fuppcrting, or extending the fpine , which laft, however, in 

 this cafe requires particular caution. 



12. Somnus. In deep all voluntary power is fufpencted, 

 Sec.1. XVIII. An unufual quantity of ilcep is often produc- 



>y weaknefs. In this cafe imall dofes of opium, -. 

 and bark, may be given with advantage. Fur the periods of 



, fee Clafs IV. 2. 4. i. 

 The fublequent ingenious obfcrvations on . of 



