OCCURRENCE OF CAUSATIVE AGENTS. 161 



the activity of the metabolic products of bacteria, which 

 do not themselves advance, as a rule, beyond the cornea. 



Sympathetic Ophthalmia. Deutschmann observed in 

 cases of sympathetic ophthalmia an infiltration of the pia 

 and the presence of phlogogenic bacteria in the optic-nerve 

 sheath of the sympathetically affected eye. He attributed 

 the sympathetic inflammation to direct invasion of the 

 microbes by way of the optic-nerve path from the primarily 

 affected eye. These observations have, however, not been 

 confirmed, and the parasitic origin of sympathetic ophthal- 

 mia must still be considered as undemonstrated. 



Chalazion is looked upon as the expression of a chronic 

 inflammation of the tarsal connective tissue that is caused 

 by the entrance of the exciting agents of inflammation into 

 the excretory ducts of the Meibomian glands, and in the 

 hair-follicles of the eyelashes. Giant-cells are invariably 

 present in the granulation-tissue of the chalazion, and 

 Tangl observed therein the presence of tubercle-bacilli. 

 This observation, however, has not been repeated, and 

 numerous inoculations of chalazion-tissue upon animals 

 have never led to the development of tuberculosis in these. 



Trachoma. Diplococci closely resembling gonococci 

 have been repeatedly demonstrated in the contents of the 

 trachoma-follicle. The transmission of the disease by 

 means of these microorganisms appears to have been suc- 

 cessful in several instances, but their specific significance is, 

 on the whole, still doubtful. 



PYEMIA AND SEPTICEMIA. 



Pyemia and septicemia are not sharply separable from 

 each other either clinically or etiologically. Both are 

 caused by the exciting agents of suppuration, with the 

 difference, however, that in relation with septicemia the 

 element of intoxication is the more conspicuous ; whereas, 

 in relation with pyemia dissemination of the bacteria by 

 way of the blood-stream and development of multiple foci 

 of suppuration (metastases) take place. So-called putrid 

 intoxication and acute malignant edema (gangrene fou- 

 droyante of the French) must not be considered as varie- 

 ties of ordinary septicemia. Both of these disorders occupy 

 a peculiar position from the etiologic point of view, as the 

 first is due to mixed infection with putrefactive bacteria, 

 ii 



