INDEX OF INFECTIOUS DISEASES. 681 
ause of pleurisy in children and of metapneumonia pleurisy, but 
that in metastatic, pyogenic, pleuritic inflammation the strepto- 
coccus or staphylococcus are the common infective agents. Pleurisy 
due to streptococcus or staphylococcus infection is not in all cases 
attended with pus formation ; the exudate in a certain proportion of 
cases may remain serous. 
In pleurisy occurring as a complication of typhoid fever the 
bacillus typhosus has been found in the exudate. Occasionally 
bacillus coli communis has been found. According to Flemming, 
about 41 per cent. of the fatal cases of pleurisy are due to tubercular 
infection. 
Pleuropneumonia of Cattle. Due to infection by the pneumo- 
bacillus liquefaciens bovis of Arloing. 
Pneumonia. Characteristic lobar pneumonia is due to infection 
by the pneumococcus, 507, 511; irregular cases are usually due to 
Friedlinder’s bacillus, streptococcus, staphylococcus, typhoid bacil- 
lus, and influenza bacillus, 325. 
Puerperal Fever. Due usually to infection by streptococcus, 
482, or colon bacillus, 453. In some fatal cases staphylococcus 
pyogenes aureus has also been found. Among other micro-organisms 
sometimes met with, and which in these cases may have been con- 
cerned in the production of the inflammatory process, are gonococcus 
and proteus vulgaris. 
Purpura Hemorrhagica. No micro-organism has been shown 
to be specific for this affection. 
Pyzmia. (See Septicemia.) 
Pyelonephritis. According to Schmidt and Aschoff (1893), 
pyelonephritis or surgical kidney is an infectious process usually due 
to bacillus coli communis. (See also Nephritis. ) 
Pyosalpinx Zweifel (1892) has shown that a certain proportion 
of the cases of pyosalpinx, if not all of them, are due to the pres- 
ence of the gonococcus, 528. In some cases the infectious agent is 
apparently streptococcus pyogenes or pneumococcus; but Zweifel 
believes that in the majority of cases in which the gonococcus is not 
found it is the infectious agent, its absence being due to the fact that 
it has died out in cases examined too late to find it. 
Relapsing Fever. Due to infection by spirillum Obermeieri, 
596. 
Rheumatic Fever. The close analogy existing between true 
rheumatism and certain of the infectious diseases, such as gonorrhcea, 
scarlet fever, and septic processes in general, which are frequently 
