EXPERIMENTAL MORPHOGENESIS 119 



considerations. Perhaps these considerations will give us 

 a very clear and simple result by convincing us that it is 

 indeed possible to analyse morphogenesis in our schematic way. 



But if the answer were a negative one ? What would 

 that suggest ? 



The full analysis of morphogenesis into a series of single 

 formative occurrences, brought about by the use of given 

 means and on the basis of given potencies, might assure 

 us, perhaps, that, though not yet, still at some future time, 

 a further sort of analysis will be possible : the analysis into 

 the elemental facts studied by the sciences of inorganic 

 nature. The organism might prove to be a machine, not 

 only in its functions but also in its very origin. 



But what are we to say if even the preliminary analysis, 

 which possibly might lead to such an ultimate result, fails ? 



Let us then set to work. Let us try to consider most 

 carefully the topic in which our concept of the formative 

 cause or stimulus may be said to be centred, the localisa- 

 tion of all morphogenetic effects. Is it always possible in 

 fact to account for the typical localisation of every 

 morphogenetic effect by the discovery of a single specific 

 formative stimulus ? You will answer me, that such an 

 analysis certainly is not possible at present. But I ask 

 you again, are there any criteria that it is possible, at least 

 in principle ; or are there any criteria which will render 

 such an aim of science impossible for all future time ? 



The Morphogenetic " System ' 



We know from our experimental work that many, if 

 not all, of the elementary organs in ontogeny show one 



