ANATOMICAL CHARACTERS. 497 



When torn or cut the exposed surface has a soft granular 

 aspect, from the existence of phigs of the sohdified material 

 entangling corpuscular blood-elements impacted in the air- 

 vesicles. This condition of sohdification and friability is 

 marked by many variations in character, not merely from the 

 variations in the anatomical structure of the lung-tissue of the 

 different animals with which we are connected, but also in 

 animals of the same species, from influences some of which are 

 easy enough of appreciation, as period of duration or intensity 

 of the action, and others less obvious and less easily under- 

 stood. 



If, in the living animal, auscultation be employed over any 

 portion of lung-structure undergoing this condition of red 

 sohdification or softening, we will not, as in the stage of en- 

 gorgement or arterial injection, detect any crepitant sound ; 

 if we are able to detect sound at all, it will be of the character 

 known as bronchial ; the vesicular structure and interconnec- 

 tive-tissue being solidified, while the air-tubes remain perme- 

 able. 



This state of coloured solidification, should the animal 

 continue to live, is not the final one ; we have, as a rule, suc- 

 ceeding this, or under certain conditions and influences 

 appearing without its intervention, the state of suppurative or 

 purulent infiltration, recognised as the third or fourth, and 

 final stage of pneumonia, and spoken of as grey hepatization or 

 softening. Occasionally a division has been attempted in this 

 condition of advanced inflammatory action by speaking of sup- 

 puration of lung-tissue of the diffuse character, as distinct from 

 the recognised grey softening or hepatization ; this is scarcely 

 applicable, for although the variations in this stage are great — 

 in some the cut surface being comparatively firm if pale- 

 coloured, in others the puriform material is so abundant as to 

 ooze freely from the recently cut surface — they are yet both 

 marked distinctly enough from the other stages by the 

 obvious existence of puriform matter appreciable to the naked 

 eye. 



Although probably in essential structural changes both con- 

 ditions of grey and red hepatization may be regarded as similar, 

 there are yet several particulars in which they are distinctive. 

 The most obvious and prominent individual feature of the 



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