400 



COLLOIDS IN BIOLOGY AND MEDICINE 



destroys it much sooner than would be expected from the extremely 

 dilute solutions employed; the germ retains the disinfectant in other 

 media or in an infected organism and only subsequently succumbs 

 to the damage the disinfectant inflicts. We must seek the essential 

 activity of the disinfectant in a modification of the living substance 

 with which the disinfectant combines or changes so that its vitai 

 function is suspended. 



I know of no experimental investigations which show what part of 

 the disinfectant is combined (fixed) and what part is adsorbed, though 

 such studies are very desirable as they would afford us clearer in- 

 sight into the nature of disinfection, and they would also be of great 

 practical significance. For the present we must be satisfied with 

 analogies which without question can be applied correctly to tho 

 principle of disinfection. Chemically, the microorganisms have so 

 much similarity to textile fibers, especially with wool and silk (to 

 mention only the great similarity in staining), that we may properly 

 employ in argument the results of W. SCHELLENS. He shook 1 gm. 

 of fiber with 50 cc. of a sublimate solution containing 1 per cent Hg 

 and found: 



1 The adsorption figures were calculated by me from the figures of SCHELLENS. 



These figures are interesting from various points of view. We 

 see that in the case of sublimate, of 3 parts of Hg, approximately 

 2 parts are adsorbed and only one is fixed. Mercuric cyanid is the one 

 substance which is only adsorbed and suffers practically no fixation ; 

 though it is true it powerfully inhibits development, it has but a 



