PYiEMIA. 49 



which, not being able to escape from tbe economy, produces 

 capillary phlebitis, od. That it is dependent on a property 

 possessed by pus of coagulating the blood. Adh. That it is 

 caused by the presence of a peculiar poison, which contaminates 

 the system." — ^(Bennett.) 



The first theory is founded upon the assumption that pus cells 

 differ from the white globules of the blood ; whereas in reality no 

 actual difference, either in size, structure, or behaviour, on the 

 addition of re-agents can be detected ; therefore, if the capillaries 

 are sufficiently large to admit the passage of the white blood 

 globule, they must consequently be large enough to admit the 

 passage of the pus cell. 



The second explanation was advanced by Cruveilhier, who, 

 on injecting mercury, ink, and other substances into the blood 

 of a living animal, found that abscesses were formed wherever 

 these accumulated ; hence it seemed to follow that the impaction 

 of certain substances in the tissues may induce local inflamma- 

 tions, and lead to abscesses ; but that such is not the necessary 

 result of admixture of pus with the blood is proved not only 

 by the previous observations, but by numerous experiments of 

 Lebert and Sedillot, in which the animals recovered. 



The third doctrine was advanced by Mr. Henry Lee, and 

 resulted from observing that when pus was mingled with 

 recently drawn blood, it coagulated more rapidly and more 

 firmly than under ordinary circumstances. 



But although this may be true as regards pus when mixed 

 with recently drawn blood, it does not follow that it induces 

 coagulation of living blood in the vessels of an animal ; and 

 numerous experiments by Lebert, Sedillot, Bennett, and the 

 late Professor Barlow, show that such does not take place : in 

 some cases death followed, in others the animals lived, and the 

 pus corpuscles were dissolved. 



The fourth theory is based upon the opinion that good pus is 

 innocuous, and that the bad effects occasionally produced depend 

 on its becoming putrid, or being otherwise altered. It is now 

 generally believed that pysemia is due to a poisonous principle 

 associated with the pus ; hence it is proposed to substitute the 

 terms ichoraemia (Virchow), or septicaemia (Vogel), for pyaemia. 



The signs of pysemia may not manifest themselves for some 

 time after the primary abscess has discharged itseK; never in 



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