HEADACH. 549 



transitory, though there is a variety in this respect according to 

 the cause. Thus, even in this plethoric state, when there is a 

 greater tendency to hsemorrhagies, there are more formal par- 

 oxysms of the headach. 



" There is another case, depending on a rheumatic affection, 

 the pain being the same with that occurring in rheumatic affec- 

 tions of other parts. Here there is an increased impetus in ves- 

 sels not suited to haemorrhagies, because they are enclosed in 

 the membrane of the muscles. To understand this, we must look 

 into the writings of the Stahlians, who tell "us, that there are 

 Congesta completa et incompleta, the former of which answer 

 to the proper haemorrhagies, and the latter to the rheumatism ; 

 so that in both cases they suppose the Molimina hcemorrhagica, 

 or an increased impetus of blood to the part to exist. This 

 doctrine, with a little improvement, would be very just. What 

 the difference in the state of the vessels is, we shall not explain 

 at present. Besides this, there is, perhaps, some difference also 

 in the causes of each affection. But however this may be, it is cer- 

 tain that there is a paroxysm of headach of the rheumatic kind. 



" There is likewise another headach of the arthritic kind, 

 which is also another of the Congesta. How far this differs from 

 the rheumatic it is difficult to explain. It differs however in 

 this, that the arthritic headach arises from an interruption of 

 the usual determination of such arthritic affections, and is re- 

 lieved by their return. 



" There is a fourth case depending on a topical fever. In- 

 termittent fevers, during an epidemic period, often operate 

 solely in producing headachs. Perhaps then we have headachs 

 precisely in the situation of intermittent^, with this difference 

 only, that they are topical instead of general. Whether there 

 are not topical fevers of other kinds, which are the foundations 

 of various headachs, is not determined, but seems probable. 



" These four species, appearing in paroxysms, are all analo- 

 gous ; and in proportion as a person is acquainted with the doctrine 

 of fevers, will he understand the state of these headachs, and their 

 proximate causes. They begin with a cold fit, or with symp- 

 toms analogous to it ; such as, a general horripitatio, and a 

 sense of coldness in the part, which is frequently succeeded by 

 a hot fit, shewing at least an increased impetus in the part itself. 



