Henriksen, A Functiorial view of Development. 2 I 



to eaeh species. That the establishment of the relations among 

 the cells is an adaptation is clearly shown in Prof. Frank R. 

 Lillies lecture on Adaptation in cleavage of the Unio and annelids 

 and among adult organisms it has given rise to the theory of 

 organic evolution. 



The relations are easily disturbed by separating the earlier 

 blastomeres or removing parts of the organism and easily inhibited 

 by change in the surronndings in which they develop. But before 

 we proeeed to illustrate this let us take one of the more striking 

 cases in recent investigations in Embryology to show that we have 

 no more right to assume that the three quartets above described 

 were preformed in the egg than the lens of the eye is preformed 

 in the epiblast opposite the optic vesicle of the embryo. It has 

 been shown that if the optic vesicle is removed no lens deve- 

 lops and the initiatory step toward the establishing of a lens will 

 take place at any point on the snrroiinding epiblast with which 

 the optic vesicle comes in contact, Thus we see clearly the optic 

 vesicle is neccessary to establish those relations which later will 

 give rise to others to form that complex organ, the lens of the 

 vertebrate eye, and we have no right to assume that it was pre- 

 formed in any part of the epiblast without begging the question 

 in explaining the phenomenon on the basis of accessory biophors, 

 etc. And just becäuse the development of an organism proceeds 

 by progressive steps one dependent on the other, instead of pre- 

 formed in the egg, it becomes unavoidable that the embryology of 

 the organism must be a shortened recapitulation of the phylogeny, 

 it must possess some of the previous relations to establish the 

 new ones. Thus the increase in phylogeny means a new adjustment 

 to form slightly different relations and an elimination of those 

 present so as to form only a few necessary steps of its phylogeny 

 for the development of the new organs. They are the rudiments 

 of its history. Thus, the Organization of the egg means only the 

 power to establish proper relations within the blastomeres, as well 

 as between these, of the two-celled stage and these again proeeed 

 to establish other relations, etc., until the equilibrium of the species 

 is reached in the full-grown animal; and the argument as you will 

 see is based on the fact that if they are disturbed new relations 

 are developed toward establishing this equilibrium. This unima- 

 ginably fine adjustment no physical science has been able to explain and 

 we can only imagine the possibility of it by considering how at 

 present slight variations or mutations arise and how they are 

 adjusted on eliminated by the factors of organic evolution, and by 

 considering the immense elapse of time which lies behind phylogeny 

 as is shown in the history of our globe. 



The relations I .vomes more and more specific as the com- 

 plexity of the do.eloping organism increases, so that at a later 

 stage no attempt of a small part of an organism, among the higher 

 animals, can establish this equilibrium; it has lost the power of 

 nutrition and growth and therefore it dies. Allow nie again to 



