in plant cells the nucleus is founi in close juxtaposition 

 to the point of this formation. Xorschelt (1889) also 

 observed that in the egg cells of the water beetle, Dyt- 

 iscus marginalis, where the eggs are supplied with nutri- 

 tive granules by surrounding cells, the nucleus sends 

 pseudopod like processes in among these granules. There 

 are also numerous observations of an exchange of granules 

 between nucleus and cytoplasm. 



In apparent contrast t-. these observations, "^alla 

 (1890) round that in the root hairs and pollen tubes of 

 some phanerogamic plants, enucleated bits of protoplasm, 

 when selected from a growing part, were able to form a new 

 cell wall: the "cellulose reaction." These observations may 

 not, however, be as contradictory as they seem, for the 

 importance of selecting a growing part suggests that we 

 may be dealig with an after effect of the nucleus: that 

 the formative substances produced by the nucleus may have 

 been already present in the protoplasm at the tine of its 

 separation. 



ouch an explanation is not applicable, however, when 

 we come to the f ormati m of starch. In the experiments of 

 Klebs quoted above, the interesting discovery was -lade 

 that non-nuclear protoplasm, nrovided it contained chlor- 

 ophyl, was ^uitc capable of forming starch in the light- 



(IB) 



