SURGICAL COMPLICATIONS AND SEQUELS OF FEVERS. 37 



arterial cases 12, ami of 43 venous eases 24 occurred in the 

 second and third weeks of the fever. Moreover the preceding 

 circumstances, such as famine, individual poverty, and the 

 deprivations of war, are sucli as impair the nutrition and the 

 circulation in the peripheral districts of tlie body. The 

 coagulation also takes place at points mechanically favorable 

 to slowing of the currents, e. g., the bifurcation of arteries and 

 the valves in the veins.' In the veins at least, as described bj' 

 Humphrey, the clots are sometimes laminated, the outer Ia3'er3 

 of decolorized fibrin, and therefoi'e the oldest, and the centre, 

 a bar-like recent coagulura of dark or black blood. 



Once that the obstruction exists in the artery, it extends by 

 additional coagulation, so that tiie collateral circulation ma}' 

 be widely and rapidly cut off. The progress of the clot can 

 often be watched from da}'' to day by the progressive annihi- 

 lation of the pulse, first, for example in the tibial, then in the 

 popliteal, then in the femoral or higher ; and by the parallel 

 progress of the gangrene. In cases of recovery this cessation 

 of the pulsation and the hard tender cord in the course of the 

 vessels are of course, the onl}', but sufficient proof of their 

 occlusion. That gangrene follows so much more frequently 

 in febrile thrombosis than after the traumatic thrombus which 

 accompanies ligation, is not surprising, in view of the condition 

 of the blood, the general enfeeblement, and the moi'e wide- 

 spread arrest of the collateral circulation. Yet, on the other 

 hand, pyemia, which has so much to favor it, especially in the 

 cases of venous thrombi, is a rare sequel. Even when it does 

 follow, it is in most cases apparently the secondary result 

 from the septic influences arising from the gangrenous parts. 



The circulation in the artery being cut off, it is not strange 

 that clots should follow in the veins, but even where both are 



' See a carefully reported case of Phlegmasia by Cole, Med. Times 

 and Gaz., 1875, i. 5. 



