368 PHILOSOPHICAL TBANSACTIONS. [aNNO 1788. 



rous openings and communications of the vessels with one another, that blood 

 flowing out of any one will empty them all equally, and that therefore it can be 

 of no consequence from what part of the body blood is evacuated. In a pleurisy, 

 for instance, where can be the difference, whether blood be taken from the right 

 or left arm, or from the vessels of the skin of the breast ? But there is a dif- 

 ference, and a great one too ; since taking a much less quantity of blood from 

 the skin of the breast, is actually known, in certain cases, from experience, to 

 cure a pleurisy, than would have had that effect if taken from the vessels in the 

 arm, and will even carry off the disease, when it could not be carried off at all 

 by evacuation from the arm : yet it is undoubtedly the very same blood in all its 

 qualities ; and in both cases the vessels of the pleura are equally emptied. The 

 act of flowing out of the blood from the vessels of the skin of the breast then 

 has an immediate action on the action of the moving parts in the pleura, and 

 carries off the inflammation independent of the circulation, or any of its laws ; 

 and so far has the knowledge of the circulation been of any advantage in this 

 case, that it had nearly thrown out topical bleeding in inflammation, which is 

 one of our most powerful remedies in the disease. In like manner, when the 

 moving flbrfes of the stomach do not contract, so as to expel any vapour that 

 may get into it, a spice applied to the skin over the stomach will, in many cases, 

 occasion these fibres to contract. Now it is well known from anatomy, that 

 there is no communication between the skin of the abdomen and the stomach ; 

 and if the spice were to act by touching these fibres, it would be the same, whe- 

 ther it was applied to the skin over the stomach, or to the skin of the arm ; for 

 in both cases it must be absorbed by the lymphatics, and carried to the left side 

 of the heart, and there and in the lungs be blended universally with the whole 

 blood, and carried by the arteries to the moving fibres of the stomach. Nay 

 more, that it would be equal, whether it was applied to the inner surface of the 

 stomach itself, or to the external skin, or any other membrane, of any other 

 cavity : for the stomach is covered with mucus, and lined with a membrane 

 which is perfectly impervious, and totally prevents any thing contained in the 

 stomach from being any way applied to the moving fibres ; it must in this case 

 therefore be likewise taken up by the lymphatics, or lacteals, and carried to the 

 heart before it could touch the moving fibres of the stomach. The maxim then, 

 arising from our knowledge of the lymphatics, would be, that it was of no con- 

 sequence where we applied a spice in cases of flatulency ; which is not true. By 

 similar reasons it might be easily shown, that all the knowledge of the proper- 

 ties of the fluids, which has been acquired by modern and accurate experiments, 

 hardly contributes any thing to the knowledge of applying medicines for the cure 

 of diseases ; and that the study of the laws of the attraction of life, or what has 

 been called muscular motion, is of considerable importance. 



