CHAPTER XI 



RELATIONS BETWEEN THE ORIENTATION AND 

 FUNCTION OF CERTAIN ELEMENTS OF THE 

 SEGMENTAL GANGLIA 



The results of some investigations carried on by 

 Garrey and myself showed that if a constant current 

 be sent through a trough in which are larvae of 

 Amblystoma, peculiar changes may be observed in 

 the postures of the animals (i). If the current passes 

 through them longitudinally from head to tail (Fig. 

 37) the back becomes convex and the ventral side 



FIG. 37. ATTITUDE OF AN AMBLYSTOMA UNDER THE INFLUENCE OF A 

 GALVANIC CURRENT PASSING FROM HEAD TO TAIL. 



FIG. 38. ATTITUDE OF AN AMBLYSTOMA WHEN THE GALVANIC CUR- 

 RENT PASSES FROM TAIL TO HEAD. 



concave. This change of position is occasioned by 

 the muscles of the ventral side (the flexors of the 

 spinal column) becoming more tense than the dorsal 



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