H. E. LEHMAN 223 



the most promising modifications of the nuclear transplantation 

 technique could involve experimental attempts to "determine" 

 labile blastula cell nuclei by pretreatment with various agents 

 including organ-specific extracts before testing their capacities for 

 differentiation. The method of nuclear transplantation has so far 

 only been used as a means of studying nuclear differentiation 

 but this technique, when explored more fully, may find a consid- 

 erably wider application in the study of other aspects of cell 

 function including svaithesis of gene-controlled materials in the 

 cytoplasm and, as Briggs and King ( 1952 ) have suggested, in 

 the study of the division process itself. 



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