46 PRACTICE OF PHYSIC. 



CHAP. VI. OF PNEUMONIA, OR PNEUMONIC 

 INFLAMMATION. 



CCCXXXIV. Under this title I mean to comprehend the 

 whole of the inflammations affecting either the viscera of the 

 thorax, or the membrane lining the interior surface of that ca- 

 vity : for neither do our diognostics serve to ascertain exactly 

 the seat of the disease ; nor does the difference in the seat of 

 the disease exhibit any considerable variation in the state of the 

 symptoms, nor lead to any difference in the method of cure. 



" In order to determine the distinction which it is proper to 

 make here, I must begin by observing, that an inflammation of 

 the pulmonic system may have three different seats in these parts : 



" First, In the mucous membrane of the trachea, and partic- 

 ularly of the bronchiag ; for in the latter case only it will ap- 

 pear as an affection of the lungs. This I take to be always the 

 case of catarrh, which I have referred to another head, that of 

 profluvia. 



"Secondly, In the cellular texture of the lungs, otherwise call- 

 ed the parenchyma of the lungs. But there are several doubts 

 with regard to the inflammation supposed to be seated in the 

 cellular textures, commonly called the parenchyma of the lungs. 

 I am adverse to admit, that any inflammation is primarily seated 

 there. So far as I can observe, the seat of all inflammation is 

 in membranous parts ; or, considering, according to the idea of 

 anatomists, all membranes as condensed cellular textures, in- 

 flammation is universally seated in such firm cellular texture 

 as we call membrane. The supposition of an inflammation 

 having a different seat, in a perfectly loose cellular texture, 

 may apply to three cases the brain, the lungs, and the liver. 

 We know that it is chiefly situated in the membranous parts 

 of these organs, and though it docs appear in the cellular tex- 

 ture or parenchymatous parts, still it is doubtful if it did not 

 begin in the membranous part, in the interior layer of some ser- 

 ous membrane, as the pia mater, pleura, peritonaeum, &c. which 

 have an exterior layer of a firmer, and an internal of a more 

 cellular texture ; and so it may imperfectly go into the more 

 loose cellular texture subjected to the membrane, although it 

 probably begins in the membranous part. 



