Pyccmia and Septicemia . 5 



the adjacent blood. It tends further to disintegration, as the 

 action of the microbes and their toxins on the leucocytes, trans- 

 forms these into pus cells, inducing softening of the mass, and 

 the washing on of individual infective pus cells and minute por- 

 tions of the clot to form infective centres and abscesses at distant 

 parts. 



If the pathogenesis of the invading microbe is weak and the 

 resistance of the leucocytes potent, such clots may remain cir- 

 cumscribed or may even be absorbed, but in the opposite conditions 

 with potent and numerous microbes and abundant and effective 

 toxins, the disposition is not only to a continuance of infection, 

 but to an acute febrile pyaemia. 



Pyaemia does not supervene at once upon a trauma as may 

 septicaemia, but only after a variable number of days, (3 to 8), 

 a peculiarity which is explained by the temporary protection of 

 the clot. By the constant accretions on its exterior, of the new 

 layers of haematoblasts and fibrin, the microbes are at first impris- 

 oned, and it is only when softening has taken place, or when the 

 coagulum has extended into the free flowing current passing into 

 a colateral trunk, that the infection is liable to be washed on in 

 dangerous amount. 



The mere presence of pus microbes or their toxins in the blood, 

 does not determine pyaemia : a modification of the intima of the 

 vessels leading to local infections with thrombosis or embolism 

 and abscess is an essential condition. This lesion of the vessels 

 may be a trauma, as from bruise, puncture, operation, ligature, or 

 it may be the extension of a disease process as in arteritis, phle- 

 bitis, atheroma, the growth of a tumor from adjacent tissues, or 

 parasitism. The seat of the secondary abscess depends primarily 

 on the location of the original suppurating centre. As such centres 

 are most commonly in the systemic circulation (osteomyelitis, 

 omphalitis, wounds, traumas) the lungs are most commonly 

 attacked, the pulmonary capillaries acting as a sieve and arresting 

 the floating infective coagula. When the primary infection comes 

 from the chylo-poietic viscera, the liver is likely to show the first 

 crop of secondary abscesses. When, on the other hand, the pri- 

 mary abscess is in the lungs, the great flow of blood through the 

 kidney renders it especially subject to secondary suppurating foci, 

 though these may form in any part of the body. 



