200 



THE INFECTIOUS DISEASES. 



' 



FIG. 91. PCS CELLS IN SUPPURATIVE IN- 

 FLAMMATION. 



Some of the cells show the marks of ne- 

 crosis and disintegration with fragmenta- 

 tion of the nuclei, etc. 



in this pklegmonous inflammation there be much serous fluid associated 

 with the cell accumulation, as is commonly the case in the earlier stages 

 of the process, the condition is 'often 

 named purulent oedema. When, on the 

 other hand, there is a more or less 

 circumscribed collection of purulent 

 exudate in the depth of the tissues or 

 organs, associated with necrosis and flu- 

 idification of the tissues involved, it is 

 customary to call the result of the proc- 

 ess an abscess. 



In some phases of exudative inflam- 

 mation, particularly those involving the 

 serous surfaces, the exudates often occur 

 together in the most variable propor- 

 tions; they are formed under the in- 

 fluence of the same agents and frequently an exudate at first simply serous 

 in character becomes fibrinous or purulent or both together. 



It will thus be seen that the exudate which is formed in suppurative 

 inflammation varies considerably in its composition and structure. 

 Primarily, pus consists of an albuminous fluid containing leucocytes, 



some monouuclears, most of them 

 polymorphonuclears (Fig. 9 i ) . 

 While the exudate is in the tissue 

 and the conditions are favorable, these 

 cells may be alive and without struc- 

 tural abnormalities. But often, and 

 especially in accumulations, they pre- 

 sent various phases of degeneration 

 albuminous or fatty or of necrosis 

 and disintegration. It is on account 

 of their relative frequency and abun- 

 dance in purulent exudates that the 

 leucocytes are regarded par excellence 

 as pus cells. But other cells may be 

 present in pus, thus in inflammation 

 of the serous membranes, such as the 

 peritoneum, pleura, etc., the exfoli- 

 ated and proliferated mesothelial cells 

 may furnish no small part of the cel- 

 lular content of the exudate. In in- 

 flammation of the mucous membranes also, the epithelial cells, either 

 new-formed or simply exfoliated, may be abundant. Furthermore, gus 

 may contain a variety of chemical substances and formed elements de- 

 pending upon the place of its formation or accumulation. Thus mucus, 

 fibrin, cell and tissue detritus, fat, and micro-organisms may be inter- 

 mingled with the pus cells. 



. 



FIG. 92. STAPHYLOCOCCUS PYOGEXES Au- 



REUS, IN AND AMONG THE PUS CELLS, FROM 

 AN ABSCESS OF THE KIDNEY. 



