ENDOCARDITIS. 



343 



both this malady and the inflammation of the inner arterial tunics, 

 from which the so-called atheroma proceeds, among the parenchyma- 

 tous inflammations. This term is applied by Virchow to the active 

 disturbances of nutrition which are provoked by an irritation, but 

 which, instead of producing an exudation between the elements of the 

 tissues, causes a swelling of the normal elements themselves, and a 

 proliferation of their cells. In endocarditis the inflammation does not 

 originate in the deeper layers of the endocardium, but upon its more 

 superficial portions. They become enlarged, are infiltrated by a liquid 

 whose chemical properties resemble that of mucin, that is, it coagu- 

 lates into the form of threads upon addition of acetic acid. In addition 

 to this, a vast formation of new cells takes place, which immediately 

 organize into connective tissue. It is only in very rare cases, in the 

 so-called ulcerative endocarditis, that the proliferation of young cells 

 goes forward with such activity that the tissue breaks down under 

 their pressure, producing a loss of substance, an ulceration of the 

 endocardium. 



The cause of endocarditis is somewhat obscure. It is seldom the 

 result of direct irritation. Bamberger has only seen two cases of 

 traumatic origin. The frequence with which the orifices and valves of 

 the heart suffer from this disease scarcely leaves any doubt that endo- 

 carditis, arising from internal causes, attacks those portions of the endo- 

 cardium by preference which are especially exposed to strain and fric- 

 tion from the action of the heart. Just as the pulmonary artery, which, 

 though otherwise rarely atheromatous, if exposed to abnormal tension 

 by hypertrophy of the right ventricle, is often attacked by atheroma ; 

 and just as the veins even undergo atheromatous degeneration when 

 distended by a current of blood from a communicating artery, so in the 

 heart, it is the narrow places, the outlets, which are most often dis- 

 eased, but especially those portions of the valves which strike against 

 one another in closing, the auricular surfaces of the mitral, and tricus- 

 pid, and the convex faces of the semilunar valves. 



Whether primary idiopathic endocarditis ever occurs, and whether 

 the disease independently can attack a previously healthy person who 

 has been exposed perhaps to cold, may be doubted, yet it is not impos- 

 sible. The great frequence of valvular disease, in individuals who pro- 

 fess never to have suffered from any acute sickness, makes it probable 

 that an idiopathic chronic endocarditis is not uncommon. In the vasl 

 majority of cases endocarditis arises in the course of acute articular 

 rheumatism (Hamberger), and all the more readily the greater the 

 number of joints attacked. It is idle to indulge in speculations as to 

 how this complication comes about, as they cannot lead to any ser- 

 viceable explanation. Although, however, acute articular rheumatism 



