PUS. 151 



more necessary than phosphates and potash-salts to render an 

 exudation truly plastic. 



Without entering further into the consideration of the inci- 

 dental morphological constituents of pus, we will at once proceed 

 to its cytoid corpuscles. On micro-chemical investigation they 

 present the following reactions. (F. P. 11, F. 3 and 4). 



If fresh pus be very much diluted with distilled water, the 

 corpuscles are seen to swell and become very pale ; the granular 

 character of their surfaces either wholly disappears or true granules 

 become detached therefrom. The interior of the corpuscles occa- 

 sionally exhibits a distinct nucleus, but more frequently only an 

 aggregation of granular matter with no distinct outlines, whilst in 

 addition to this, the corpuscles also exhibit in their interior fine 

 granules, which are in a state of active molecular motion. Henle 

 has especially called attention to the circumstance that, on the 

 addition of water, some of the pus-corpuscles burst, and allow 

 their viscid contents to escape, which then become dissolved in 

 the dilute serum. The corpuscles then appear collapsed, are much 

 darker, and still contain nuclei. The action of the water is best 

 observed in the cytoid corpuscles of the buccal mucous membrane ; 

 the lenticular nucleus, which may be here very readily recognised, 

 is generally simple, that is to say, not cleft, and is then situated so 

 close to the investing membrane of the corpuscle that it frequently 

 appears as if it were attached to this membrane on the outside of 

 the cell. This nucleus is brought more prominently into view on 

 the addition of water, which does not cause it to split. 



Strong alcohol causes the serum of the pus to coagulate, and 

 hence renders a microscopical examination of the corpuscle una- 

 vailing. But when spirit containing 23% of alcohol is employed, 

 which induces no turbidity of the pus- serum, the corpuscles 

 appear distorted, somewhat elongated, and, as it were, caudate or 

 pointed. 



In ether, free from alcohol, the corpuscles are also distorted. 



When fresh pus is treated with very dilute mineral acids, as 

 hydrochloric acid (1 part in 2,800 parts of water), nitric acid (1 

 part of anhydrous acid in 2,000 parts of water), phosphoric acid 

 (1 part in 1,500 parts), or tolerably dilute organic acids, as acetic, 

 lactic, oxalic, tartaric, racemic, or citric acids, no coagulation takes 

 place, but the pus- corpuscles swell to so great a degree that they 

 frequently attain double their original size. The granular appear- 

 ance, which may very probably have been owing to plaits in the 

 capsule, disappears ; the latter, which appears to be extremely 



