646 THE POPULAR SCIENCE MONTHLY. 



inflamed organ are affected by the blister. We do not know whether 

 they are dilated or contracted. It is most likely, however, that the}^ 

 are contracted, the contraction lessening the pressure of blood upon the 

 inflamed tissues, and thus diminishing the pain in somewhat the same 

 way as we relieve the throbbing ia an inflamed finger by holding the 

 hand above the head, or by compressing the brachial artery. This is 

 rendered probable by the experiments of Zulzer, who found that when 

 a blister was applied to the back of a rabbit for a length of time the 

 skin and the muscles immediately below it were red and congested, but 

 the deeper layers of the muscles, the pleura, and even the lung on the 

 same side, were pale and anemic. There are few inflammations of the 

 internal organs in which blisters to the surface are not serviceable, but 

 much has yet to be done to ascertain the exact points at which they 

 ought to be applied in order to produce their maximum effect. Thus 

 it is said that in sciatica a blister to the heel will sometimes afford 

 relief, while one applied in the neighborhood of the nerve itself has 

 little or no effect. 



The effect of poultices is probably difi'erent from that of blisters, 

 although ultimately productive of similar relief; for, if we again take 

 the simjDle instance of a finger inflamed in consequence of a thorn 

 having run into it, we find that we can relieve the pain in two waj^s, 

 either by putting the hand into cold water or by plunging the finger 

 into a warm poultice. Both of these measures, apparently so dis- 

 similar, will produce a like result in regard to the inflamed point ; that 

 is, both will lessen the pressure of blood in the vessels where stasis has 

 already taken place. The cold, applied to the whole of the hand, will 

 cause the arteries leading to the finger to contract, and will thus 

 diminish the supply of blood to the inflamed part, and lessen the pres- 

 sure in the blocked capillaries. The warm poultice will also lessen the 

 pressure, not by diminishing the flow of blood to the part, but by 

 dilating the vessels around tlie point of stasis, and affording the blood 

 a ready exit into the veins. In the case of internal organs, the blister 

 applied to the skin probably acts like the cold applied to the finger, 

 while the warm poultice placed upon the surface of the thorax or 

 abdomen affects the deeper lying organs in the same way as it does the 

 superficial ones, the warmth penetrating through the thin thoracic or 

 abdominal parietes. On this account, when we wish to relieve pain in 

 the chest or belly, we ought to make our poultices in a particular way. 

 The common practice of mixing the linseed-meal with hot water, and 

 applying it directly to the skin, is quite wrong, because if we do not 

 wish to burn the patient we must wait until a great portion of the heat 

 has been lost. The proper method is to take a flannel bag (the size of 

 the poultice required), to fill this with the linseed poultice as hot as it 

 can possibly be made, and to put between this and the skin a second 

 piece of flannel, so that there shall be at least two thicknesses of flannel 

 between the skin and the poultice itself. Above the poultice should be 



