GENERAL DISEASES. 307 



is abundant, the urine is proportionately concentrated and 

 scanty. On the other hand, during winter, when the cuta- 

 neous transpiration is checked by the agency of external 

 cold, the flow of dilute water from the kidneys in strikingly 

 augmented. * All this is well known to be compatible with 

 the maintenance of the most perfect health. But supposing 

 the exhalation from one of these surfaces to be much dimin- 

 ished, or to cease, without a corresponding increase of func- 

 tion in the exterior, then dropsy, in some form or degree, is 

 very apt to arise. The aqueous liquid thus detained in the 

 bloodvessels seeks, and at length finds, some unnatural and 

 inward vent, ind is poured forth into the areolar tissue, or 

 into the cavities bounded by the serous membranes. 



" If water be injected, in some quantity, into the blood- 

 vessels of a living animal, the animal soon perishes — dying 

 generally by coma, or by suffocation ; and when the carcase 

 is examined the lungs are found to be charged with serous 

 liquid ; or water is discovered in the areolar tissue ot some 

 other part, or in the shut serous membrane. If, however, 

 the animal be first bled and then a quantity of water injected 

 equal to the quantity of blood abstracted, the injection is 

 followed by no serious consequences. 



" Facts like these throw, as it seems to me, a strong light 

 on a confessedly obscure part of pathology. It appears that 

 und ;r \ arious circumstances the bloodvessels may receive a 

 considerable and unwonted accession of watery fluid, and that 

 they are very prone to get rid of the redundance. When 

 they empty themselves through some free surface, their pre- 

 ternatural distension is relieved by a flux. If, on the other 

 hand, the surface be that of a shut sac, in discharging their 

 superfluity they cause a dropsy. Why sometimes this organ, 

 and sometimes that, is selected as the channel by which the 

 superabundant water shall be thrown out of the vessels,, we 

 can seldom tell." 



Chronic or Passive Ascites is more commonly seen in old 

 * This is especially noticeable after bathing. 



