AND ANIMAL LIFE. 321 



abdomen ; it is therefore probable, if pressure 

 affected the vessels to the extent which is gene- 

 rally imagined, that the circulation would be en- 

 tirely obstructed, or, at least, evidently disturbed, 

 which, however, is far from being the case. 



b. If internal pressure diminished the calibre 

 of the vessels to the extent supposed, we should 

 certainly expect great disorder in the sanguife- 

 rous system, whenever this power was even 

 moderately exerted. We have seldom the en- 

 larged and oedematous extremities till general 

 debility be present ; and this condition is often 

 remarked when we have no internal pressure to 

 account for it. 



c. The only function immediately relieved by 

 the operation of paracentesis abdominis, is that 

 of respiration. It is extremely difficult, or almost 

 impossible, to breathe in a supine posture when 

 the hydropic accumulation is considerable. 



CCCLXIX. Whatever alteration the abdomi- 

 nal vessels may suffer from the watery evacua- 

 tion, I am persuaded that the change, neither 

 directly nor indirectly, is the cause of syncope. 

 During the collection of the fluid the diaphragm 

 has been pushed up, presenting an almost un- 

 yielding convex surface to the lungs. The cavity 

 of the thorax, the capacity and mobility of the 

 lungs, have consequently been much lessened and 

 impeded. When the fluid is evacuated, the 

 diaphragm almost instantly resumes its proper 

 x 



