THE CIRCULATORY SYSTEM. 463 



phlebitis with thrombosis, which frequently complicates infectious dis 

 eases such as typhoid fever, pneumonia, etc. , the bacteria present are 

 frequently not those which are the excitants of the primary disease. 



The most important results of phlebitis are usually those which 

 depend upon the introduction into the blood of infectious or other emboli 

 (see page 76). The relationship between non-infectious thrombi and 

 phlebitis is in many cases not clear. 1 



FIG. 257. TUBERCULOUS PHLEBITIS.- 

 The section is from one of the pulmonary veins in a child dead of acute general miliary tuberculosis. 



Chronic Periphlebitis results in thickening, principally of the outer 

 coats of the veins, but the inner coats may also be involved. The sur- 

 rounding tissue may be also thickened and coalesce with the walls of the 

 vein. There may or may not be thrombosis. 



Chronic Endophlebitis is a not very common lesion, of the same general 

 character as chronic endarteritis, with which it is often associated. 

 More or less circumscribed patches of new connective tissue are formed 

 in the inner coats, which may undergo fatty or calcareous degeneration. 



Tuberculous Inflammation of the walls of the veins may occur as an 

 extension of the process from without or from a lodgment of the tubercle 

 bacilli in the blood current on the intima (Fig. 257). This is not iufre- 

 quent in the pulmonary veins, and Weigert has called attention to the 

 fact that in acute miliary tuberculosis the growth of tubercle tissue into 

 the lumma of these veins from tuberculous lymph-nodes is of frequent 

 occurrence and readily explains the topography and mode of occurrence 

 of the general disease. The tubercle bacilli which are present in the 

 tuberculous tissue growing into the lumen of the veins find thus an easy 

 distribution. 2 



Syphilitic Inflammation may involve the walls of the veins either as 

 gummy tumors or as more diffuse thickenings. 



1 Consult in this connection Welch on Thrombosis, Albutt's "System of Medicine," 

 vol. vi., p. 170. 



2 Bee references under Miliary Tuberculosis, p. 218. 



