EXPERIMENTAL MORPHOGENESIS 65 



(Fig. 6). But now there resulted not chaos, but the normal 

 organisation : therefore it was disproved in the strictest way 

 that nuclear divisions have any bearing on the origin 

 of organisation ; at least as far as the divisions during 

 cleavage come into account. 



On the egg of the frog (O. Hertwig), and on the egg of 

 annelids (E. B. Wilson), my pressure experiments have been 

 carried out with the same result. 1 



ON THE INTIMATE STRUCTURE OF THE PROTOPLASM OF THE 



GERM 



Nuclear division, as we have seen, cannot be the basis 

 'of organ ogenesis, and all we know about the whole develop- 

 ment of isolated blastomeres seems to show that there 

 exists nothing responsible for differentiation in the protoplasm 

 either. 



But would that be possible ? It cannot appear possible 

 on a more profound consideration of the nature of morpho- 

 genesis, it seems to me : as the untypical agents of the 

 medium cannot be responsible in any way for the origin 

 of a form combination which is most typical and specific, 

 there must be somewhere in the egg itself a certain factor 

 which is responsible at least for the general orientation 

 and symmetry of it. Considerations of this kind led me, 

 as early as 1893, 2 to urge the hypothesis that there 



[ In the pressure experiments I had altered the relative position of the 

 nuclei in origine. In later years I succeeded in disturbing the arrangement 

 of the fully formed cells of the eight-cell stage, and in getting normal larvae 

 in spite of that in many cases. But as this series of experiments is not free 

 from certain complications which in part will be understood later on (see 

 page 73) it must suffice here to have mentioned them. (For further informa- 

 tion see my paper in Archiv. f. Entwickelungsmechanik, xiv., 1902, page 500.) 



- Mitteil. Neapel. 11, 1893. 



5 



