448 



WHEELER P. DAVEY 



these groups of experiments it has been shown possible to dupH- 

 cate results time after time, subject only to those general limita- 

 tions which are inseparable from biological work. Typical ex- 

 periments in each group will be described below. Apparatus 

 and technique were the same as in the work previously reported. 



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/40 /60 Mrs 



