Introductory Remarks 9 



In any case, we can state today that the cytoplasm 

 contains the rough preformation of the future embryo. 

 This would show then that the idea of the organism 

 being a mosaic of Mendelian characters which have 

 to be put into place by "supergenes" is unnecessary. 

 If the egg is already the embryo in the rough we can 

 imagine the Mendelian factors as giving rise to specific 

 substances which go into the circulation and start or 

 accelerate different chemical reactions in different 

 parts of the embryo, and thereby call forth the finer 

 details characteristic of the variety and the individual. 

 The idea that the egg is the future embryo is supported 

 by the fact that we can call forth a normal organism 

 from an unfertilized egg by artificial means; while it is 

 apparently impossible to cause the spermatozoon to 

 develop into an organism outside the egg. 



4. The influence of the whole on the parts is no- 

 where shown more strikingly than in the field of re- 

 generation. It is known that pieces cut from the plant 

 or animal may give rise to new growth which in many 

 cases will restore somewhat the original organism. 

 Instead of asking what is the cause of this so-called 

 regeneration we may ask, why the same pieces do not 

 regenerate as long as they are parts of the whole. In 

 this form the mysterious influence of the whole over 

 its parts is put into the foreground. We shall see that 

 growth takes place in certain cells when certain sub- 

 stances in the circulation can collect there. The 



