72 Motion of the 



with one another, because they all become turgid 

 together, whilst under the medium ligature applied 

 above the elbow ; and if any single small vein be 

 pricked with a lancet, they all speedily shrink, and 

 disburthening themselves into this they subside almost 

 simultaneously. 



These considerations will enable any one to under- 

 stand the nature of the attraction that is exerted by 

 ligatures, and perchance of fluxes generally; how, for 

 example, the veins when compressed by a bandage of 

 medium tightness applied above the elbow, the blood 

 cannot escape, whilst it still continues to be driven in, 

 to wit, by the forcing power of the heart, by which the 

 parts are of necessity filled, gorged with blood. And 

 how should it be otherwise ? Heat and pain and the 

 vis vacui draw, indeed ; but in such wise only that parts 

 are filled, not preternaturally distended or gorged, not 

 so suddenly and violently overwhelmed with the charge 

 of blood forced in upon them, that the flesh is lacerated 

 and the vessels ruptured. Nothing of the kind as an 

 effect of heat, or pain, or the vacuum force, is either 

 credible or demonstrable. 



Besides, the ligature is competent to occasion the 

 afflux in question without either pain, or heat, or vis 

 vacui. Were pain in any way the cause, how should 

 it happen that, with the arm bound above the elbow, 

 the hand and fingers should swell below the bandage, 

 and their veins become distended ? The pressure of 

 the bandage certainly prevents the blood from getting 

 there by the veins. And then, wherefore is there 

 neither swelling nor repletion of the veins, nor any 

 sign or symptom of attraction or afflux, above the 

 ligature ? But this is the obvious cause of the preter- 

 natural attraction and swelling below the bandage, and 

 in the hand and fingers, that the blood is entering 

 abundantly, and with force, but cannot pass out 

 again. 



Now, is not this the cause of all tumefaction, as 



