586 



PLEURISY. 



times the exudation consists of almost pure blood, which separates into 

 clots and serum. This form constitutes the Hcemorrhagic pleurisy. 

 The fluid thus exuded loses its colour, the heavier parts fall at the most 

 declining part of the pleuritic sac ; the exudation, which continues, 

 coagulates more slowly, and forms free and floating false membranes. 

 The exudation assumes a greyish dirty appearance, sometimes resem- 

 bling pus. This form constitutes what the author calls pleurisy with 

 empyema. This state lasts for some time ; generally between the 7th 

 and 15th day exudation becomes more slow; it is more serous and less 

 fibrinous. Then the exudation increases, but tends to clear up by 

 precipitation and absorption of the constituent particles, and the liquid 

 is then clear, serous, limpid, yellowish, slightly greenish. This con- 

 stitutes the pleurisy with hydrothorax, and lasts for a more or less time, 

 until death ensues, or the animal recovers. 



"Such is the typical course of the acute pleurisy, but it may vary 

 according to circumstances, so that the exudation from reddish may 

 clear up at once without passing through the intermediate or greyish 

 state. In some other cases the liquid will ever persist, more or less, 

 thick and muddy. 



"From the preceding observations the author concludes that, in 

 the regular course of pleuris} r , the exudation passes through at least 

 three different forms corresponding to three distinct periods; but these 

 periods vary in length, they may be more or less long, according to 

 circumstances. The 43 cases observed are classified in the following 

 table : 



"M. Saint-Cyr draws these conclusions: 



1st. There is not a distinct limit between the first two periods. 

 2nd. These two periods have together a duration averaging from 

 8 to 15 days. 



