1 56 Lectures on Bacteria. [^ xiii. 



subject to be infected to the results of infection is shown by the 

 fact, that in sick-rooms and institutions in which consumptive 

 patients remain the year through, it is not every one who is suc- 

 cessfully infected with tuberculosis. This fact is in accordance 

 with the general knowledge which we possess of individual or 

 specific differences in susceptibility to the attacks of parasites. 



The foregoing facts and views are not affected by the state- 

 ments of Malassez and Vignal, who describe a form of tuber- 

 culosis with a copious growth of Micrococcus, which they call 

 'tuberculose zoogloique,' and in which they sometimes found 

 the Bacillus and sometimes not. Supposing these accounts to 

 be correct, we must assume with the clear results of Koch's in- 

 vestigations before us that there is either some complication 

 here, or that we are deaUng with some disease resembling 

 ordinary tuberculosis but different from it in so far as it is caused 

 by a different parasite. 



4. Gonorrhoeal affections (61). These are inflammations 

 of the mucous membrane of the urethra and of the conjunc- 

 tiva of the eye accompanied by suppuration and occurring 

 in the human species. Purulent conjunctivitis in new-born 

 children, ophthalmia neonatorum, may certainly be classed 

 with them. 



One of the characteristic peculiarities of these maladies is that 

 they are highly infectious, and it has long been known that in- 

 fection is due to the purulent secretion of the patient. The 

 infection of healthy human eyes takes place, as Hirschberg says, 

 with the certainty of a physical experiment. With the same 

 certainty there is found in the infectious matter a large Micro- 

 coccus, which was discovered by Neisser and named by him 

 Gonococcus (Fig. 20), chiefly appearing to be attached to the 

 surface of the epithelial and pus-cells, according to recent 

 observations really penetrating a slight distance into the body 

 of the cells, less often lying between them. It should be added 

 that the number of the cells beset with the Gonococcus is always 

 relatively small and varies from case to case. 



