IS .Henriksen, A Functional view of Development. 



so ist es doch wahrscheinlich, und bei sehr großen Vielfachen obiger 

 Zahlen sogar sicher, dass unter den übrig gebliebenen gerade soviel 

 Individuen das überdurchschnittliche, als das unterdurchschnittliche 

 Geruchsvermögen besitzen. Unter ihnen aber haben dann eben 

 doch die mit dem überdurchschnittlichen Geruchsvermögen weit 

 größere Chancen, tatsächlich zur Fortpflanzung und damit zur Ver- 

 erbung ihres Vorzugs zu gelangen. 



Nur wenn der Vorzug von einem Nachteil in anderer Hinsicht 

 untrennbar begleitet wird, modifiziert sich das Dargelegte, und 

 dann wird niemand bezweifeln, dass der Vorzug für die Auslese 

 bedeutungslos bleiben kann. 



A Functional view of Development. 1 ) 



Everything in nature tends towards a State of equilibrium 



which is peculiar to itself. 



The questions of preformation and epigenesis are the first to 

 attract the attention of the student of biology and I believe tliat 

 many students have feit as I have when I say; that the speculative 

 zoologists have gone further in their speculation on germ plasm 

 structure than can possibly be allowed from a scientific point of 

 view. I further believe that many of our speculative zoologists 

 offen have forgotten the general tendencies indicated in all growing 

 organism as well as the important factors of physiology and the 

 effect of the external Stimuli. And, therefore do the most of our 

 theories and hypothesis laeve to the logician's „Residue" a larger 

 number of facts than bear up their hypothesis or the continually 

 beg the question tili they become „Reductio ad absurdum". 



It is not my object here to take up a discussion of the tech- 

 nicalities of development but merely to indicate what seem to me 

 to be the general tendencies in every developing organism and to 

 show that every developing organism tends toward an equilibrium 

 peculiar to itself and possesses in some degree the power to restore 

 any disturbance in this harmony. 



The first question which attracts the student"' s attention in 

 stüdying the development of organism is the immense potentialities 

 of the egg and soon he learns that the size of the egg and the 

 size of the organism to which it gives rise have no relations to 

 each other. Very often the smaller organism may arise from the 

 larger egg and vice versa. 



He next asks himself the question what part of the germ cell 

 is actually concerned in the formation of the new organism and 

 he finds the cytologist's answer that the nucleus is the important 

 part and the chromosomes are the bearer of Heredity. He may 



1) A paper read before the Zoological Club of Obio State Universitv. 



