I 



DIPHTHERITIC INFLAMMATION. 431 



3. Diphtheritic Inflammation. 



§ 370. After the exclusion of what is commonly known as- 

 ^^ pharyngeal diphtheria"' from the domain of diphtheritic in- 

 flammation, the extent of the latter remains comparatively 

 limited. We have already touched upon the essential features- 

 of the process, in our account of the ^' diphtheritic pock" (§ 298). 

 It consists of an infiltration of newly-formed cells into the sub- 

 epithelial connective tissue, as contrasted with the entire mucosa ; 

 an infiltration so abundant as to compress the vessels, and to 

 arrest both circulation and nutrition. Inasmuch as a certain 

 amount of corpuscular infiltration of the subepithelial connective 

 tissue occurs in connexion with every catarrh, as well as ^s^ith 

 the croupous form of inflammation, diphtheria may be regarded 

 as merely a quantitative increase or excess of this morbid pro- 

 liferation ; true diphtheria having no claim to be regarded 

 as a specific process in the same degree as croup. To the 

 naked eye, it presents certain characters which have led to 

 its being contrasted with the '^ Inflammatio pseudo-membra- 

 nacea" as an ^^Inflammatio membranacea " ; I refer to the 

 formation of a tough, felted membrane of a greyish- white colour, 

 often mottled with shades of red and green (due to blood-pig- 

 ment), raised to the height of about half a line above the level of 

 the mucous surface, penetrating downwards into its substance to 

 the same extent, and intimately blended with it. This mem- 

 brane is not a deposit upon, or a secretion from the mucous 

 surface ; it is the mucous membrane itself, so much of it at least 

 as has been at once tumefied and deprived of blood by the 

 excessive corpuscular infiltration. This condition has been 

 compared, not inaptly, to mortification caused by a chemical 

 irritant, to a corrosion, and the diphtheritic membrane has been 

 called a ^^ diphtheritic slough" ; the membrane is indeed a caput 

 mortuum^ it cannot enter upon any changes save putrefaction 

 and decomposition ; we have only to inquire how it is set free 

 from its close organic union with the mucous membrane, and 

 cast off. Simple inspection is enough to show us that a sharp 

 line of demarcation separates the living tissue from the dead ; 

 but a number of connective-tissue fibres, blood-vessels, nerves, 

 and elastic fibres, pass from the living into the dead parts ; and 

 these must all give way before separation can occur. The means 



