i Physiological Morphology 103 



same part of the protoplasm escapes, we must conclude that 

 every part of the protoplasm may give rise to fully developed 

 embryos without regard to preformed germ-regions.^ In many 

 eggs a repeated outflow of the protoplasm takes place. In such 

 cases each of the drops of the protoplasm may give rise to an 

 embryo, and I obtained not only double embryos, but triplets 

 and quadruplets all grown together. 



It is remarkable that the development of these monstrosities 

 goes on nearly at the same rate as that of the normal embryo, 

 provided they are equally well supplied with oxygen and equally 

 protected from microbes and infusoria. The development in 

 most eggs takes place in so regular and typical a manner that it 

 seems as if there were a prearrangement of some kind. It is, 

 however, perfectly well possible that this prearrangement 

 consists in a separation of different liquid substances in the 

 ovum by the molecular qualities of these liquids. Such a 

 separation, of course, might be called a preformation of germ- 

 regions, but it would be something totally different from what 

 is now understood by that term. 



V. theoretical remarks 



1. All life phenomena are determined by chemical processes. 

 This is equally the case whether we have to do with the contrac- 

 tion of a muscle, with the process of secretion, or with the forma- 

 tion of an embryo or a single organ. One of the steps that 

 physiological morphology has to take is to show in every case 

 the connecting link between the chemical processes and the 

 formation of organs. I have tried to show that in a few cases 

 at least this connecting link was to be sought in the changes of 

 osmotic pressure determined by the chemical changes which 

 take place in the growing organ. 



But this fact alone does not explain why it is that we get 



1 in the light of more recent experiments it is possible, that after all only such 

 pieces can develop into a normal embryo which contain the different germ-regions 

 (1912). 



