102 OF STIMULUS AND EXERTION. SECT. XII. 7, 



actions of the minute veflels of the various parts 

 of the external Ikin are not only aflbciated with 

 each other, but are ftrongly aflbciated with thofe 

 of fome of the internal membranes, and particu- 

 larly of the ftomach. Hence when the exertion of 

 the ftomach is lefs than natural, and indigeftion 

 and heart-burn fucceed, nothing fo certainly re- 

 moves thefe fymptoms as the ftimulus of a blifter 

 on the back. The coldnefs of the extremities, as 

 of the nofe, ears, or fingers, are hence the beft in- 

 dication for the fuccefsful application of blifters. 



5, Decreafe the ftimulus for a time. By leflen- 

 ing the quantity of heat for a minute or two by 

 going into the cold bath, a great accumulation of 

 ienfoiial power is produced ; for not only the mi- 

 nute veflels of the whole external fkin for a time 

 become inactive, as appears by their palenefs ; but 

 the minute veflels of the lungs lofe much of their 

 activity alfo by concert with thofe of the fkin, as 

 appears from the difficulty of breathing at firll 

 going into cold water. On emerging from the 

 bath the fenforial power is thrown into great exer- 

 tion by the ftimulus of the common degree of the 

 warmth of the atmofphere, and a great production 

 of animal heat is the confequence. The longer a 

 perfbn continues in the cold bath {he greater muft 

 be the prefent inertion of a great part of the fyftem, 

 and in confequence a greater accumulation of fen- 

 forial power. Whence M. Pome recommends 

 fome melancholy patients to be kept from two 

 to fix hours in fpring-water, and in baths ftill 

 colder. 



6. Decreafe the ftimulus for a time below the 

 natural, and then increafe it above natural. The ef- 

 fect of this procefs, improperly ufed, is feen in giving 

 much food, or applying much warmth, to thofe 

 who have been previoufly expofed to great hunger, 



or to great cold. The accumulated fenforial power 

 o 



IS 



