138 MANTON COPELAND. 



approximately the same time. It is possible, however, that 

 nervous impulses travel only to the muscles, and that the 

 latter in some way exert a stimulating influence on the over- 

 lying ciliated epithelium. Further investigation, both his- 

 tological and physiological, is planned which, it is hoped, will 

 throw more light on the problem. 



LITERATURE CITED. 

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