550 , PRACTICE OF PHYSIC. 



Sometimes this is communicated to the rest of the system, and 

 produces a more frequent pulse. They terminate also like 

 fevers, with hsemorrhagies, with sweatings either in the part itself, 

 or more generally, and oftentimes with swellings of a particular 

 part, as in the rheumatism. Frequently they are without any 

 sensible resolution ; but this also happens in many fevers. 



"The principal headachs, then, we refer to topical fever. As 

 in other fevers, so here is a cold and hot fit in various degrees. 

 In some fevers there is only a cold fit, which immediately kills the 

 patient ; in others it is succeeded by a hot fit, and this having 

 various proportions to the cold fit, and with various resolutions. 



" These fevers of headach are also of different kinds, and 

 mark out the different prevalency of the cold and hot fits. To 

 explain this, we must make a few remarks upon the nature of 

 pains. There are some pains depending on a stimulus, or some 

 acrid matter applied to the part : but as this is common to every 

 part of the system we shall omit it here, #nd only take notice 

 of those pains which are more immediately connected with the 

 vascular system, and occur in the extremities of vessels. These 

 are of two kinds, one of which proceeding from distention, and 

 which occurs in the plethoric headach, is well understood, and 

 perhaps the only one generally thought of. The other kind of 

 pain is analogous to an external force compressing and constrict- 

 ing the nerves ; and perhaps of this kind is the pain arising 

 from spasmodic constrictions. Such too is the pain arising 

 from cold ; this condenses all bodies, and constringes the ex- 

 tremities of nerves ; but whether it acts merely thus, or pro- 

 duces spasmodic constrictions, is difficult to determine. Such 

 constrictions do arise from cold, and are relieved by heat ; thus 

 many headachs are accompanied with a sense of cold ; and there 

 are instances of the same in other parts, as in particular joints, 

 which are only removed by restoring the impetus of the blood 

 to them ; and though this causes a distention, it cures them. 

 This pain then appears to be opposite to the distending pain, 

 which occurs chiefly in attacks of headach and fevers, and 

 often in chronic rheumatisms. In several instances of head- 

 ach, these two pains are more or less mixed ; thus in the febrile 

 headach itself, the pain coming before the cold fit, or accom- 

 panying it, cannot be of the distending kind, but must certainly 



