164 CHEMICAL EFFECT ON GROWTH G DIFFERENTIATION 



Histological examination is desirable but not necessary to identify the various types of 

 developmental abnormalities. Material may be fixed in Bouin's for sectioning, or in 

 10% formaldehyde for dissection. 



There is a current interest in mitotic inhibitors such as colchicine and the nitrogen n-ius- 

 tards, which indirectly affect development. It is expected that within the next few years 

 the chemical separation of ontogenetic processes will be extended to great lengths by the 

 use of such and related chemical substances on the aniphibian embryo. 



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9"26S. 



"If there be a better way of securing understanding ttian by the 

 method of science, human history a)id human experience liave not yet 

 revealed it. " 



A. J. Carlson 



