TRANSPLANTING NEURAL TUBE OF AMBLYSTOMA 



177 



through the transplant by May 7th (fig. 2, G), seven days after 

 the operation. 



The frontal section shows the transplant united with both 

 stumps, but the readjustment is not as complete as in the 

 two preceding cases, which was to have been expected from the 

 shorter duration of time between operation and fixing in the case 

 of G9. In the figure the original anterior end of the transplant 

 is to the right. Owing to a shift in position, its axis cuts that of 



Fig. 16 Embryo G9, frontal section. Anterior end up. 



Fig. 17 A, EmbryoT.L.9, May26. Operated April 8. 5, sagittal section. 



the embryo diagonally, the anterior end of the transplant lying 

 cephalad to its posterior end. The shift forward of the anterior 

 end of the transplant might have been due to factors connected 

 with the process of bridging the stumps, or it might have been 

 due to lack of success in implanting the excised tube at right 

 angles to the embryonic axis at the time of operating. However, 

 the fact that a similar shift in position of the transplanted tube 

 has been noted in many other operated embryos points to the 

 conclusion that it is not the result of accident in technique, but 

 rather an indication of a definite orientation of the transplant. 



