SPASMODIC AFFECTIONS. 443 



arising from causes producing an accumulation of blood in the 

 great vessels near to the heart. 



MCCCLIX. A third head of the cases of palpitation, is of 

 those arising from a more violent and rapid influx of the nervous 

 power into the muscular fibres of the heart. It is in this man- 

 ner that I suppose various causes acting in the brain, and par- 

 ticularly certain emotions of the mind, occasion palpitation. 



MCCCLX. A fourth head of the cases of palpitation, is of 

 those arising from causes producing a weakness in the action of 

 the heart, by diminishing the energy of the brain with respect 

 to it. That such causes operate in producing palpitation, I pre- 

 sume from hence, that all the several causes mentioned above 

 (MCLXXVII, et seq.) 9 as in this manner producing syncope, 

 do often produce palpitation. It is on this ground that these 

 two diseases are affections frequently occurring in the same per- 

 son, as the same causes may occasion the one or the other, ac- 

 cording to the force of the cause and mobility of the person 

 acted upon. It seems to be a law of the human economy, that 

 a degree of debility occurring in any function often produces a 

 more vigorous exertion of the same, or at least an effort towards 

 it, and that commonly in a convulsive manner. 



I apprehend it to be the convulsive action, frequently ending 

 in some degree of a spasm, that gives occasion to the intermit- 

 tent pulse so frequently accompanying palpitation. 



MCCCLXI. A fifth head of the cases of palpitation may 

 perhaps be of those arising from a peculiar irritability or mo- 

 bility of the heart. This, indeed, may be considered as a pre- 

 disponent cause only, giving occasion to the action of the great- 

 er part of the causes recited above. But it is proper to observe, 

 that this predisposition is often the chief part of the remote 

 cause ; insomuch, that many of the causes producing palpita- 

 tion would not have this effect but in persons peculiarly predis- 

 posed. This head, therefore, of the cases of palpitation, often 

 requires to be distinguished from all the rest. 



MCCCLXII. After thus marking the several cases and 

 causes of palpitation, I think it necessary, with a view to the 

 cure of this disease, to observe that the several causes of it may 

 be again reduced to two heads. The first is, of those consisting 

 in, or depending upon certain organic affections of the heart it- 



