FROM DISEASE GERMS. 223 



impelling force by which the blood is driven into the 

 capillary vessels, and this may end fatally. Any local 

 disturbance of the capillary circulation gives rise to 

 various phenomena according to the precise sea"t of 

 the change. Interruption of the capillary circulation, 

 over even a small area, in part of a tissue or organ, 

 may lead to the death of that part. In this way boils, 

 and carbuncles, and sloughs are produced, and when 

 the area is extended, mortification of a considerable 

 portion of tissue, it may be of a considerable part of a 

 limb, is occasioned. Partial interruption of the capil- 

 lary circulation may give rise to inflammation only, 

 as has been described in pages 122, 123 ; and in many 

 cases, even though a considerable portion of tissue 

 may be affected, if only a few capillaries here and 

 there continue to transmit blood, mortification is 

 averted, though inflammation very damaging to the 

 part may result. 



In fevers, as has been already mentioned on 

 page 179, the degree of severity of the attack is deter- 

 mined by the extent of capillary circulation which is 

 implicated, and the force of the heart's action. The 

 capillary circulation being equally involved in two 

 cases, in one the force of the heart being very good, 

 in the other very weak, death may result in the latter 

 and complete recovery in the former. The heart's 

 action being weak, it is reasonable to suppose that if 

 by artificial means its force could be increased for the 

 time, the prospects of recovery would thereby be- 



