SURFACES 31 



layed supplementary process may indicate a slow diffusion of the 

 adsorbed substance into the adsorbent, as J. DAVIS has demon- 

 strated in the case of the adsorption of iodin by charcoal. In the 

 fixation of dyes by textile fibers we can assume the probable occur- 

 rence of secondary chemical processes. I believe that many mis- 

 understandings in the moot questions of toxin-antitoxin fixation might 

 have been avoided, if there had been a clear understanding of the 

 various phenomena which may occur in the course of an adsorption 

 process. 



Finally, it must be mentioned that catalyzers are adsorbed (all 

 organic ferments are colloids) . By reason of adsorption, the reaction 

 in a solution may be stopped; or in other cases, the reaction may be 

 accelerated upon the adsorbent. Thus oxidations may be brought 

 about by concentration of oxygen on the adsorbent or reductions by 

 concentration of hydrogen (C. PAALS' reduction of nitrobenzol by 

 colloidal palladium and other chemical reactions.) 



The fundamental conception of adsorption is so illuminating that 

 the attempt has been made to explain a large series of biological 

 processes as adsorption phenomena (enzym action, union of toxin and 

 antitoxin, etc.). I cannot better express the results of all this work 

 than in the words of W. BiLTZ,* 4 who, in another connection, says, 

 " The testing ... of the material in accordance with an exact 

 method, such as is involved in the use of a formula, offers the worker 

 a rather mingled pleasure, as may be noted from the great difference 

 between the results of experiment and of calculation. If it were not 

 for the novelty of the subject investigated, . . . the result which is 

 so frequently accepted for the sake of the principle, would be of very 

 little importance." 



I should like to add further: The adsorption formula is a rock 

 which, Lorelei-like, has magically attracted numberless scientific 

 voyagers only to wreck many of them. Every complicated phe- 

 nomenon of higher organisms, which consists partly of chemical, 

 partly of solution phenomena and perhaps partly of true adsorption, 

 must assume the general character of an adsorption and have a 

 formula which seems a cross between a chemical process and a solu- 

 tion. Thus, if a biological phenomenon seems to suit the formula of 

 an adsorption, this may be merely a sign post, which, alas, many an 

 investigator may mistake for the goal. 



What then is the biological significance of what we have distinguished 

 as chemical combination, solution and adsorption? Here we approach 

 the most important principle governing the processes in the living 

 organism; it is what P. EHRLICH describes as distribution. The de- 

 veloping and the fully developed organism are constantly receiving 



