DILATATION OF VEINS. 265 



of the curv^e bulges more than its concavity, and a saccuLar dila- 

 tation is the result, appended to the vein just as a saccular aneu- 

 rism is appended to an artery. Supposing this process to be 

 repeated at every fresh curve which the vessel makes, the vein 

 must come at last to appear as though it were entirely made up 

 of an alternating series of saccular aneurisms. This is the fully- 

 developed " varicose state" which is usually found involving all 

 the veins of a plexus, or the collective radicles of a large venous 

 trunk. This is usually the point at which phlebectasy culminates. 

 Only the "varicose tumour" can fairly be put higher; and this 

 is confined to one particular locality, namely the ha?morrhoidal 

 plexus. 



§ 230. The venous plexuses of the true pelvis and its outlet 

 stand foremost among the veins of the body in their tendency to 

 become dilated. This is partly owing to their anastomotic con- 

 nexions with the portal vein (Vena haemorrhoidalis interna), 

 which render them liable to all those influences which interfere 

 with the portal circulation, without conferring any of the com- 

 pensatory advantages accruing to the latter from intra-abdominal 

 pressure ; another cause may be sought in the frequent and 

 prolonged congestion to which these parts are exposed during 

 the performance of the sexual functions. Varicosity of the vesical 

 plexus underlies those morbid changes about the neck of the 

 bladder (catarrh of the mucous membrane, moderate enlargement 

 of the prostate) which are so common in old people, and are 

 usually known as haemorrhoids of the bladder. 



Dilatation of the ha^morrhoidal plexus (true haemorrhoids) 

 begins with congestion of the venous radicles in the lax sub- 

 mucous tissue of the rectum close to the anus. This is speedily 

 associated with a mucous catarrh of the surface, and, as I myself 

 have found, with a trifling overgrowth of the mucous follicles. 

 At a later stage, the changes in the mucous membrane recede, 

 and the phlebectasy proceeds to the development of large plexuses 

 of varicose veins which push the mucous membrane before them, 

 and form a ring of transverse ruga^ round the anal aperture. 

 The dilatation finally concentrates itself at one or more points of 

 these ruga}, which develope into rounded protuberances, and 

 ultimately into fungoid tumours of considerable size. 



If we cut through a large haBmorrhoidal nodule, we may see, 

 even without a microscope, that the chief part of its texture is 



