112 DISEASES OF THE LUNGS. 



analogous facts, shewing its progress from growth to de- 

 velopment — although the observations have not l}een made 

 on horses — are enabled to arrive at some explanation. 



The primary seat of these alterations would appear to 

 be the inter-lobular cellular tissue ; but^ whether from 

 inflammation of that tissue, or from the effects of inflam- 

 mation in the parenchyma of the lung, or in the pleura, is 

 still matter of dispute between Dupuy and Delafond. 

 Infiltration into this cellular tissue — at first of a serous, 

 afterwards of a plastic nature — is evidently the forerunner 

 of the change ; the reabsorption of the eff'used fluid, as 

 observed by Delafond, being slower within the cellular 

 tissue than within the parenchyma, it follows that the fluid, 

 become organically allied with the cellular membrane, may 

 continue long after the cessation of the inflammation of the 

 parenchyma, and form plastic layers, and kinds of partitions 

 inclosing the pulmonary lobules. I have observed, adds 

 he, these layers grown thick and indurated, surrounding 

 abnormal productions developed in the very heart of the 

 lung — tubercles, for example — to resist the disorganization 

 of these morbid tissues, and still remain walls of cavities 

 containing the mollified matter. Sometimes, in the same 

 situations, we meet with disorganized masses of lung 

 resulting from partial gangrene. These layers or par- 

 titions, while they continue to increase their dimensions, 

 so compress the pulmonary tissue that they atrophize it, 

 render it light-coloured, dense, and impermeable to air. 

 According to Delafond, therefore, the white and grey 

 indurations would be approaches to pulmonary atrophy: we, 

 however, think that this holds true in regard only to the 

 grey induration, and that in the white induration, properly 

 so called, the parenchyma of the lung has completely dis- 

 appeared, through absorption, and nothing remains save the 

 eellular tissue indurated. Let us not forget to add, that 

 the white induration is not constantly met with around 

 tubercles; on the contrary, under many circumstances, the 

 pulmonary tissue surrounding these crude heterologous 

 masses presents simply a reddish areola. 



