708 



SOFTENING AND INDURATION. 



The colour of an indurated lung may be 

 light or dark grey, or brown, and rarely pale. 

 A section of a piece of indurated lung shows 

 the circular apertures of the bronchi and 

 larger blood-vessels, surrounded by a dense 

 tissue in which no vesicular structure is seen. 

 The fibrinous dense lymph which produces 

 these changes frequently becomes the nidus 

 for tubercular deposit. 



Partial indurations are found around tuber- 

 cular cavities and abscesses, and around collec- 

 tions of miliary, or of larger tubercular masses. 

 In certain obstructive diseases of the heart 

 the circulation in the lungs is so impeded, 

 that effusion of blood, constituting pulmonary 

 apoplexy, or effusion of lymph, producing 

 general increase of density of the whole lung, 

 may occur. 



Long continued pressure by a pleuritic 

 effusion, has the effect of rendering the lung 

 nearly solid and impervious to air. 



In treating of alterations in the cohesion of 

 mucous, serous, and articular membranes, it 

 is necessary to premise that they consist of 

 a basement membrane sustaining epithelium 

 cells and supported by sub-basement areolar 

 tissue in which vessels, nerves, and absorb- 

 ents, are found. 



The nutrition of the basement membrane 

 and the proper development of the epithelium 

 cells depend upon the amount and health of 

 the fluid parts of the blood supplied to them 

 by the capillaries of the sub-basement tissue. 

 It is evident that any morbid state of this 

 tissue will influence the integrity of the base- 

 ment membrane and the epithelium cells ; and 

 it is known that, for the most part, physical 

 alterations of these last depend upon such 

 rnorlnd states, and that these changes are most 

 likely to happen where the cellular structure 

 is loose and considerable in amount. 



Softening has been found in all serous and 

 fibro-serous membranes, and may be produced 

 by inflammatory action and by a defective and 

 perverted state of the general nutrition of the 

 body. 



The lining membrane of the heart is fre- 

 quently softened, being at the same time 

 redder and more vascular than usual. It is 

 occasionally so soft as to peel very readily 

 from the muscular structure ; a like state of 

 the pericardium exists with effusion of pus 

 into its cavity. Softening of the internal 

 membrane of the venous system is found of 

 either a deep red or pale colour ; the tissue 

 is very lacerable and breaks down into a pu!p 

 under the scalpel ; it may be caused by phle- 

 bitis, by the pressure of a considerable column 

 of blood, especially when the valves have 

 been obliterated ; and is found in cases of 

 malignant fever, scurvy, and whenever the 

 fluids are greatly altered. Post mortem 

 softening is frequent enough to raise our sus- 

 picions, and great allowance must be made 

 for the macerating and colouring properties 

 of the blood. 



Chronic softening of the internal membrane 

 of arteries is occasionally found ; when so 

 affected the serous tissue is easily lacerable, 



and such solutions of continuity are deter- 

 mined by causes, which ought in health to 

 have no influence. Portions of the interior 

 lining membrane may be found retracted and 

 rolled up within the canal, so that with the 

 effusion of lymph which generally occurs at 

 the same time, and the consequent coagula- 

 tion of a small portion of blood, the artery 

 may become completely obstructed and ob- 

 literated in a part of its course. Occa- 

 sionally, the arteries of the upper and lower 

 extremities become thus affected in succes- 

 sion, on the employment of the slightest 

 exertion, indicating a very extensive affection 

 of the nutrition of the arterial system. We 

 find, in cases of anaemia, and where athe- 

 roma is being deposited, considerable dimi- 

 nution of the general tenacity of the large 

 vessels. 



Softening of the arachnoid, 'peritoneum, 

 and pleura is generally found where there is 

 effusion of pus, or blood into the sub-base- 

 ment tissue ; it rarely occurs when lymph is 

 thrown out into the serous cavity, but seems 

 to be a more advanced phenomenon of in- 

 flammation, or, rather, is produced by inflam- 

 mation of a more intense and destructive 

 character. 



Dalmas ascribes nearly all serous softenings 

 to diseased states of the subserous cellular 

 tissue, and we find constantly that on account 

 of the altered state of this cellular structure, 

 the peritoneum and pleura may be stripped 

 off large spaces of the parts they cover ; it is 

 notorious, that in the pelvis sero-sanguineous 

 effusion into the subserous cellular tissue, and 

 consequent lacerability of the serous mem- 

 brane, frequently occur. Pulpy degeneration 

 of synovial membrane is a kind of softening 

 with a perverted state of the nutrition of the 

 tissue. 



Softening of mucous membranes is gene- 

 rally produced by inflammatory causes : it is 

 most frequently noticed, and is best studied, 

 in the alimentary canal, part or the whole of 

 which may be affected ; it is most frequently 

 observed at the end of the ilium, in the de- 

 pending portion of the colon, and in the cae- 

 cum ; in the right and left hypochondriac re- 

 gions, and in the sigmoid flexure. 



Softening of the mucous membrane in ge- 

 neral, or of any one or more of its elements in 

 particular, presents various degrees. In the 

 first degree, the mucous membrane, instead of 

 posses.sing that degree of cohesion which per- 

 mits of its being detached from the submucous 

 tissue, breaks as soon as it is seized between 

 the fingers or blades of the forceps ; in the 

 second degree, the edge of a scalpel, or the 

 finger, pressed lightly over its surface, converts 

 it into a soft and somewhat opaque creamy 

 looking pulp ; and, in the third stage, it is so 

 soft that it is removed with ease by a slight 

 stream of water. In this stage portions of the 

 mucous membrane are found partially or en- 

 tirely destroyed, and having been removed by 

 the fluid contents of the stomach or intes- 

 tines, as the case may be, during life, the sub- 

 mucous cellular tissue is thus found destitute 



