BIO-DYNAMICS 81 



past. This being understood we may fitly view most tendencies 

 of growth as the resultants of those positive and negative 

 confluents, symbiotics and anti-biotics, in the dynamic make- 

 up of organisms and species spoken of above. 



Klebs also states: "The regular fluctuation about a 

 mean according to the rule of probability is often attributed 

 to some law underlying variability. But there is no such law 

 which forces a plant to vary in a particular manner, since 

 every experimental investigation shows, as we have already 

 observed, that the fluctuation of characters depends on fluctua- 

 tions in external factors." But as fluctuations of 

 "characters" depend, I believe, mainly on behaviour and bio- 

 economic function, past and present (a fact on which I must 

 insist all the more, the less it is likely to be disclosed by labora- 

 tory methods) it follows, in my view, that there is a perfect 

 web of dynamics, constituted by the web of domestic and 

 biological interactions, in which every organism and every 

 species is involved ; the degree to which they are involved 

 determining and pre-determining all important developments 

 and "tendencies." The law underlying variability, which 

 Prof. Klebs totally fails to recognise, is the law of organic 

 solidarity, involving the " law of bio-economic specialisation " 

 and of symbiogenesis, and for the rest, so far as minor and 

 local phenomena are concerned, the law of action and reaction. 

 Many powerful components in the heritable dynamic constitu- 

 tion of a species are due to. past ancestral endeavours, and the 

 biological correlations they have established in the web of life ; 

 others are due to behaviour calculated to establish opposite 

 effects. In any case the terms "symbiotics" and "anti- 

 biotics" seem to be both, quantitatively and historically 

 speaking, more adequate and more explanatory than the term 

 "specific structure," which is vague. Prof. Klebs also states 

 that " the historical sequence of events of which the organism 

 is the expression (italics mine) can only be treated hypo- 

 thetically with the help of factors supplied by comparative 

 morphology, the history of development, geographical 



