610 AFFECTIONS OF THE INTESTINAL CANAL. 



the intestines into the intestinal veins ; we know that the increased 

 fulness of the portal vein, from this cause, obstructs the escape of blood 

 from the splenic vein, and that consequently the spleen is enlarged 

 every time that digestion goes on. But it readily follows that from 

 excess in eating and drinking the fulness of the portal veins is in- 

 creased, and is more permanent, and that consequently other veins 

 which open into the portal veins may dilate, and from repeated ex- 

 cesses may remain dilated. This explanation is hypothetical, it is true, 

 but it is not more so than other explanations that have been offered for 

 the occurrence of haemorrhoids from excess in eating and drinking. 



3. The obstruction which impedes the escape of blood from the 

 hffimorrhoidal plexus may lie beyond the liver, in the chest. Thus 

 we often see haemorrhoids develop in lung-diseases where the capilla- 

 ries are compressed or atrophied ; the patients considering them as the 

 cause, not as the result, of their chest-disease. In the same way 

 haemorrhoids develop from heart-affections, along with other results of 

 overfilling of the veins. 



The above-mentioned obstructions to the circulation do not usually 

 suffice to cause haemorrhoids ; their frequency is not proportionate to 

 the amount of the obstruction ; they are often absent when the escape 

 of blood from the haemorrhoidal plexus is greatly interfered with, 

 wliile in other cases, where there is no perceptible obstruction except a 

 temporary constipation, they become excessive. There is an analo- 

 gous condition in the varicose veins of the legs of women during 

 pregnancy ; in some women the varicose veins appear during the first 

 months, in others they do not occur even during the latter months, in 

 spite of large amounts of liquor amnii, large children, or the most un- 

 favorable position of the child. This goes to prove that the walls of 

 the veins are less resistant in some persons than in others, and that 

 this diminished tonicity of the walls of the vessels is most important 

 for the occurrence of phlebectasias anywhere, and of haemorrhoids in 

 particular. This abnormal lack of resistance in the walls of the veins 

 is in many cases congenital. The fact, that in certain families all the 

 members for several generations suffer from haemorrhoids, cannot be 

 denied, and can only be explained by the supposition that a peculiar 

 state of the vessels is hereditary. In other cases the want of resist- 

 ance is undoubtedly acquired, and is probably induced by the disturb- 

 ance of nutrition in the walls of the vessels from the chronic catarrh 

 of the rectum. We have learned that dilatation of the veins is one of 

 the anatomical appearances of chronic catarrh in all the mucous mem 

 branes, and hence can understand that the veins of the rectum, which 

 from their position are peculiarly disposed to dilatation, should in a 

 similar way become varicose from catarrh of the mucous membrane of 



