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DEOrSICAL SWELLINGS. 253 



in the larger veius there is a retarded current, which in its turn checks 

 the circulation in the lesser veins. These vessels then become congested. 

 By distension their coats become thin, and ultimately the more fluid 

 parts of the blood percolate through them. Hence may arise Anasarca 

 or general dropsy. Affection of the heart is itself a frequent after-result 

 of influenza, pneumonia, and other debilitating diseases. 



Local retardation of the circulation, as indicated by dropsical swell- 

 ings in particular parts, will generally be found to be due to derange- 

 ment of the internal organs of the part. Diseases of the liver, spleen, 

 or kidneys, for instance, are apt to hinder the venous circulation of the 

 neighbouring parts, and in this way may become a cause of dropsical 

 Bwellings in the belly and hind legs. Again, disease of the lungs, when 

 combined with pleuritis, is a frequent cause of water on the chest. 



In the above and such like cases the dropsical swelling is ftu'ther 

 augmented by the accumulation of those fluid particles which are secreted 

 from all structures, and which in health are taken up by the action of 

 the capillaries and absorbents. When, however, these vessels are them- 

 selves overcharged, they are obviously unable to absorb the waste fluids. 



Dropsical swellings cannot, however, always be traced to actual disease 

 of particular organs. They often depend on a faulty condition of the 

 blood arising from debilitating disease. The blood in such cases having 

 become thin and Avatery, is then prone to permeate through the walls of 

 the blood-vessels. 



Further, when the blood has got into a debilitated condition, it fails 

 to nourish the system properly, and hence again the action of the heart 

 is weakened. 



Dropsy may also occur from any cause, such as a sudden chill or 

 exposure, which disturbs or arrests the two processes of exhalation and 

 absorption, natural to all secreting surfaces in health ; or from external 

 injury. 



512. Causes of Hard or Inflammatory Dropsical SiceUings. 



The second kind of dropsical swellings are distinguished from the fore- 

 going by the symptoms of heat, tenderness, and pain, result from conges- 

 tion of the blood-vessels under the influence of inflammatory action. 



The abnormal disposition to effusion, as the result of congestion, 

 genera,lly arises from a weak or debilitated constitution, or from a circu- 

 lation which has become deficient in tone and vigour. The attacks of 

 inflammation, which end in drojDsical swellings, are generally very axute. 

 The swelling itself in such cases is formed veiy suddenly and rapidly. 



513. Treatment. 



The treatment, though it will necessarily vary in some degree accord- 

 ing to the causes from which the dropsical swelling proceeds, may never- 

 theless be divided, firstly, into the means of removing the effused fluid, 

 and secondly, the removal of the causes from which the eft'usion has 

 proceeded. 



