LYMPHATIC VESSELS. 103 
wall. In some cases the production of new tissue is so great as to 
obstruct the lumen of the vessel (obliterating endarteritis). The new 
tissue produced in chYonic arteritis is apt to be the seat of fatty or 
calcareous degeneration. The term atheroma has been applied to 
these changes, and by them erosions or ulcerlike patches are produced 
in the vessel walls. 
(3) Syphilitie arteritis. In this form there is a new growth of 
tissue resembling ordinary connective tissue. 
(4) Tubercular arteritis produces the same changes as tubercular 
inflammation elsewhere. 
VEINS. 
What is phlebectasia ? 
It is a dilatation of a vein and may be seen as a simple dilatation, 
uniformly cylindrical or fusiform in shape, as a cirsoid dilatation, the 
vessel being not only uniformly dilated cylindrically but also increased 
in length, and lastly as a varecose dilatation, 7. e., dilatation of a cir- 
cumscribed portion of the vesselwall into a globular sac. 
What is phlebitis ? 
It is an inflammation of the wall of a vein; when implicating the 
outer wall it is called a periphlebitis and when affecting the inner wall 
an endophlebitis. The acute forms of phlebitis are of the exudative 
type of inflammation, the exudation coming from the walls of the 
vasa Vasorulm. 
Describe the different varieties of phlebitis. 
If the inflammation starts as a periphlebitis the vesselwalls are 
swollen, congested and infiltrated with serum and pus. If it starts as 
an endophlebitis the entire vesselwall is eventually similarly involved. 
Tn all cases there is the formation of a thrombus which may be absorbed, 
or remain and obliterate the vein, or degenerate and be carried into the 
general circulation as embolic masses. Chronic periphlebitis produces 
a thickening of the outer coats of the vein. Chronic endophlebitis is 
rare, but when it occurs produces about the same effect as chronic en- 
darteritis. Syphilitic inflammation may produce gummata in the 
vesselwalls or a diffuse thickening. Tubercular inflammation may 
be produced by tubercle bacilli in the blood or by invasion from foci 
of tubercular inflammation adjacent to the veins. 
LYMPHATIC VESSELS. 
To what is lymphangitis due and what changes does it produce ? 
Lymphangitis or inflammation of the walls of the lymphatic vessels 
