OF THE VEINS. 303 



in the external vena snphena of a man who died with an ulcer 

 on the leg. I have observed that the parietes of the veins are 

 thicker on the side which touches an artery, than in the re- 

 mainder of their circumference, and I have once seen in an 

 old man a femoral vein ossified on the side next to the artery, 

 which itself was ossified throughout its circumference and for 

 some extent of its length. 



Morbid productions are sometimes observed under the form 

 of vegetation, at the internal surface of the veins, whether 

 the affected vein be surrounded by similar productions, or 

 not. 



455. The dilatation of the veins is very frequent, and is 

 of various kinds; sometimes the whole venous system is af- 

 fected by it; very often dilatation affects one or some veins 

 only, which constitutes varix. Almost every part of the body 

 may be the seat of it ; however, the most depending parts are 

 those most subject to it, as the inferior limbs, the genital or- 

 gans and the anus; it is also the most superficial veins, as the 

 subcutaneous, which are oftener affected. The augmentation 

 of the volume is not only in the circular dimension, but vari- 

 cose veins form a great many flexuosities which are ascribable 

 to the increase of their length. Sometimes dilatations of very 

 little extent, and confined to a part of the circumference of 

 the vein are found, either alone, or together with more gene- 

 ral dilatations. Varicose aneurism is another kind of dilata- 

 tion depending on the accidental communication of an artery 

 and a vein, and on the passage of the blood from the former 

 into the latter. This affection is commonly accompanied with 

 a remarkable thickening of the parietes of the elongated and 

 dilated vein. Moreover a consecutive aneurism is sometimes 

 formed between the two vessels: this case constitutes the va- 

 ricose aneurism. 



456. Veins become sometimes narrow in consequence of 

 the thickening of their parietes; they are sometimes closed by 

 the effect of plastic inflammation; sometimes they are com- 

 pressed by neighbouring tumours, or embraced within a liga- 

 ture. In those cases, in which their cavity is obliterated, 



and in which circulation no longer occurs, the blood passes 

 40 



