ADAPTATION 187 



unknown character takes its place, and nothing, indeed, is 

 against the assumption that this organisation may include 

 factors which actually drive ions or compounds to the side 

 of higher concentration, which indeed drive them by " doing 

 work," if we like to speak in terms of energy ; and these 

 factors included in organisation may very well be of a true 

 physical or chemical nature. 1 



I lay great stress upon these statements, as I should like 

 to be as careful as possible in the admission of anything 

 like a " proof ' of vitalism. It was want of scientific 

 criticism and rigid logic that discredited the old vitalism ; 

 we must render our work as difficult as possible to our- 

 selves, we must hold the so-called " machine theory " of life 

 as long as possible, we must hold it until we are really 

 forced to give it up. 



In a more general form we now can sum up our 

 discussion by saying : There never are adaptations in 

 physiology, requiring any special analysis, where there are 

 only complications or even apparent deviations from the 

 purely physico-chemical type of events which are, so to 

 say, statical, i.e. fixed in quantity or quality, however 

 peculiar or typically complicated they may be ; all such 

 peculiarities indeed, may properly be called " adapted," that 

 is to say, very well fitted to perform a specific part in 

 the service of normal general functioning, and they are 

 " adapted " to their part by virtue of a certain " adapted- 

 ness " of the organisation ; but they are not " adaptations ' : 

 in any sense of the word. 



1 According to investigations of the last two years, the physics of colloids 

 seems to play as important a part in physiology as osmosis does ; we here 

 meet "means" of functioning just as we have already had "means" of 

 organogenesis. 



