40(3 MUCOUS MEMBRANES. 



or of disordei^ conii)licated by tliem. The term '*' catarrh " la} -^ 

 stress on only one, tliough certainly the most prominent phe- 

 nomenon of the disease, sc. the increased secretion from the 

 mucous surface. We must hear in mind, however, that the 

 increased secretion can never occur without a simidtaneous 

 liypersemia of the mucous membrane, and that this hyper99mia 

 is the proximate cause of the increased secretion, and the more 

 or less remote cause of farther troubles, of swelling, ha3mor- 

 rhage, pigmentation, hypertrophy, (fcc, all of which must be 

 included in any complete view of the morbid anatomy of mucous 

 catarrh. 



Hyperemia must accordingly be regarded as the anatomi- 

 cal basis of catarrh. It may either be active or j^assive. In the 

 former event, it is the primary result of some antecedent irrita- 

 tion ; in the latter, it lasts for a long time before catarrhal, 

 inflammation is set up — it acts as a predisposing cause ; (I am 

 thinking of the bronchial catarrh of heart disease, of the gastro- 

 intestinal catarrh associated with portal obstruction, of the 

 catarrhal affections of the rectum and bladder due to piles). 

 AVhether we are justified in assuming that the catarrh ij^ 

 actually excited in these cases by some special exacerbation of 

 the existing hyperai'mia, or even by some modification in its 

 passive character, I cannot take it upon me to decide. To my 

 mind, it appears more profitable to inquire how far, and in what 

 localities, the normal structure of the mucous tract favours the 

 origin or the continuance of hyper?3mia. And first, we must 

 recollect that owing to the tenuity and permeability of the epi~ 

 thelial stratum, the access of external irritants to the irritable- 

 elements of the mucous membrane is far easier than in the skin ; 

 moreover, that there is no elastic covering, like the horny lamina 

 of the cuticle, to check the turgescence of the capillaries ; nay, 

 the softness of the parenchyma sets no limit to their disten- 

 sion. The relations in which the contractions of the muscular 

 coat of the bowel stand towards the distribution of blood in the 

 mucous coat, are of peculiar interest. The small arteries and 

 Aeins, which carry the blood to and from the capillary networks- 

 of the gastro-intestinal mucous membrane, penetrate, as is well 

 known, obliquely through the muscular coat. Here they receive 

 a sheath of loose connective tissue, which, in the case of the 

 arteries, is tolerably wide, so that a considerable space is left 



