" Third species. Uniform dilatation of the veins with increased thickness of the parietes.
" Fourth species. Dilatation of the veins at intervals with thickening of the parietes at the points where the dilatations exist.
" In these two latter species, the vessel in creases in length as well as in breadth, and in consequence becomes quite tortuous in its course.
" Fifth species. Dilatation of the veins, with the development of septa or partitions, which divide the interior of the vessel into small compartments, that allow the blood to stag nate or to coagulate, &c.
" Sixth species. Dilatation of the vein, its in terior being divided into a number of separate compartments, as in the preceding species, and in addition its parietes drilled by a number of minute holes, which allow the blood to pass from the vein into the surrounding cel lular tissue," &c.
These include all the forms of phlebectesis as far as systematic division is concerned.
The first species simply includes a general predominance of the venous system,— a dis proportionate size of the veins. It is of very frequent occurrence, and is indicated by a plethora or distinctness of the veins of the subcutaneous system. This is often seen in the veins of the back of the hand. It is not to be considered strictly morbid, — it is in many individuals an original conformation, and in others merely temporary, the result of warmth, strong exercise, pressure on a venous trunk, &c. It is common, nay gene ral, in old people, though the healthiest. It may be here observed that the capacity of veins, as well as that of arteries, increases with age.
The second species represents a condition unquestionably morbid. It consists in a dila tation of the vein at the expense of its walls, they becoming attenuated in proportion to the increase of the vessel's calibre. This appears to consist essentially in a separating of the longitudinal fibres of the outer coat, by which the internal membrane is permitted to dilate or protrude. The dilatation is seldom cy lindrical, it is usually unequal and in pouches.
These pouches are usually more or less globular or oval; sometimes, however, they are con stricted, or form pear-shaped, or even pedun culated, tumours.
The third and fourth species of Andral's division are modifications of the same condi tion, and seem to be in many cases the direct hut gradual result of the first. Whether the dilatation be general and equable, or partial and irregular, the thickening is confined to the dilated portion, and is doubtless a re parative condition, — an effort to resist by increased strength of the vessel's walls any further stretching ; and it may be ob served that in this thickened form of phlebec tesis, those large, pouchy, and tumour-like, dilatations do not occur. In these forms the dilatation is more regular and cylindrical, or increasing somewhat evenly in passing from one part of the vein to another. In almost all these cases there is increased length, some times very considerable, so as to make the vein assume a serpentine or tortuous course; in some instances the vein remains perfectly straight. The increased thickness arises from the superaddition of fibrous tissue in the ex ternal coat, probably developed from a sub inflammatory plastic exudation among the normal tissue of the outer coat, itself an effect of the stretching, in the dilatation of the vein. The amount of thickening varies in different cases : in those fully formed it is often very considerable. The increased thickness cf the vessel's walls prevents it from collapsing when cut through : it remains patent like an artery. The colour of its tissue differs, however, from the arterial; it is reddish white, and pale, like the normal venous tissue. Besides thickening of the coats of the veins, they become inde finite and very hard ; the outer coat becomes completely blended with the areolar tissue of the sheath of the vessels ; by this means the walls, which are often thicker than those of an artery of the same size, are with difficulty pressed together.