JOHN A. KOLMER 1127 



De Witt has observed that these compounds also display a high bactericidal ac- 

 tivity for tubercle bacilli; for example, mercurochrome was observed to inhibit the 

 growth of the tubercle bacillus completely in a dilution of 1:5,000 and partially at 

 1:10,000; mercurophen inhibited it completely in dilutions of 1:50,000. Mercuro- 

 chrome in a dilution of i : 100, but not in higher dilutions, killed tubercle bacilli in 

 twenty-four hours so that they would not infect guinea pigs. On the other hand, 

 mercurophen, while it did not kill uniformly in less than twenty-four hours, killed in 

 dilutions of i : 10,000 in twenty-four hours, and the development of the disease in 

 guinea pigs inoculated with the exposed tubercle bacilli was generally delayed much 

 longer than in the controls, even after shorter exposure to dilutions of 1:5,000 and 

 1 : 10,000. 



The silver salts appear to be somewhat more selective for the gram negative cocci 

 and especially the gonococcus. 



In so far as compounds of copper and gold are concerned, most attention has been 

 devoted to their effects upon tubercle bacilli, and it may be that they possess in slight 

 degree some selective effects for these organisms. But compounds of copper and gold 

 are, as a whole, relatively feeble bactericides and especially in comparison with the 

 compounds of mercury. 



Apparently, compounds of tin and zinc have not been studied from the standpoint 

 of selective bacteriostasis, but according to the results of my own limited studies, the 

 ordinary inorganic salts do not display any evidences of this property except that they 

 seem to be slightly more effective against the gram positive cocci like staphylococci, 

 streptococci, and pneumococci than against gram negative bacilli like B. coli com- 

 munis and B. typhosus. 



Various organic compounds of arsenic have long been used in the treatment of 

 bacterial infections but more for their possible dynamogenic than bactericidal effects. 

 Arsphenamin and neoarsphenamin display feeble bactericidal activities in vitro and 

 especially in water or saline solutions, and possibly these compounds are somewhat 

 more bactericidal for streptococci than staphylococci; but the differences are only 

 slight and easily accounted for by other factors. 



lodin and compounds of iodin are worthy of brief mention in relation to tubercu- 

 losis since they have been long advocated by some physicians in the treatment of this 

 disease, although De Witt and Sherman found that Lugol's solution had very little 

 bactericidal activity, since in full strength the solution was unable to kill all bacilU. 

 Tincture of iodin has a well-marked bactericidal effect upon staphylococci and 

 streptococci, accounting for its popularity as a disinfectant of the skin and for the 

 treatment of local infections by topical application, but its effects in vivo are very 

 much reduced ; to the best of my knowledge it does not display any particular selective 

 bacteriostasis and certainly not for Sp. pallida or B. tuberculosis. 



The bacteriostatic and bactericidal activity of cresote, guaiacol, and their deriva- 

 tives in relation to the chemotherapy of tuberculosis of the lungs have long held a 

 place of interest in the treatment of not only this disease but likewise in the treatment 

 of non-tuberculous bronchitis; furthermore, the question of their possible specific bac- 

 tericidal effects for tubercle bacilli as well as for the organisms of simple bronchitis 

 and secondary infection of tuberculous tissues, such as streptococci, staphylococci, 



