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BLISTERS IN PERICARDITIS, ETC, 453 



should have found the membrane dry and injected, without any 

 deposit whatever on its surface. The irritation caused by the 

 application of the blister to the thoracic wall acted reflexly 

 through the vaso-motor centre in the medulla oblongata, and 

 induced contraction of the pericardial arteries, and a more or 

 less complete return to the normal condition. In the case of 

 E. B., it might be said that perhaps the friction would have 

 disappeared even had no blister been applied ; but it is improb- 

 able that in the case of J. E. it would have reappeared on a 

 succeeding day, had its first disappearance been spontaneous, 

 and not the effect of the blister. The cessation of pain in the 

 joints I also attribute to contraction of the arteries in them, 

 induced by the blister, which had thus had an effect similar to 

 tliat of a hair seton in Zulzer's experiment. Several other cases 

 of acute rheumatism which I have had under my care this 

 autumn have convinced me of the efficacy of blisters to the 

 joints in young persons, especially those suffering from a first 

 attack, and in whom the vessels and tissues are probably 

 normal ; but in elderly persons wlio have suffered from repeated 

 attacks, the benefit derived from blisters has not been great. 



Having now considered the action of blisters as counter- 

 irritants, let us turn for an instant to their action as irritants. 

 One of the best means of treating a callous ulcer is to blister it 

 Here the irritation of the blister dilates the vessels around the 

 ulcer, and by affording a free supply of blood, bringing fresh 

 oxygen and fresh nutriment, the ulcer is healed just like those 

 on the eye iu Sinitzin's experiments. 



The points which I have tried to show in this paper are — 



1. That dilatation of blood-vessels, and a rapid circulation 

 through them, is advantageous for the tissues, and leads to 

 increased growth and more rapid repair. While this arterial or 

 active congestion is beneficial, venous or passive congestion is 

 injurious. 



2. The application of an irritant induces dilatation of the 

 vessels, and a free current of blood through them. This will 

 help to repair any injury done to the tissues by the irritant, so 

 that the injury, to a certain extent, brings its own remedy. 



3. Arterial congestion and inflammation are entirely different 



