482 E. J. LUND 



in the position indicated by a current density of 1 in figure 2, D. 

 Camera-lucida drawings of this series at the end of the experi- 

 ment are shown in plate 2, B, branch IV. The actual serial 

 order as well as the actual orientation with reference to the 

 electric current is shown in the drawing. 



The internodes from branch number III were similarly placed 

 in serial order in the position represented by a current density 

 of ^ in figure 2, D. Their serial order from base to apex of the 

 branch and actual orientation in the electric current are similarly 

 shown in plate 2, B, branch III. Internodes from branches, 

 II and I were placed similarly in current densities of | and j, 

 respectively, and similarly shown in plate 2, A, branches II and I. 



The current density at position 1 figure 2, D, varied during the 

 experiment from about 60 5 to 100 8, and consequently the 

 current densities at positions ^, ^, and I varied in precisely 

 corresponding proportions. 



Twenty-three hours after beginning the experiment the 

 extreme apical internodes of branch IV showed only slight 

 growth on the ends turned toward the anode. In branch III 

 the same result was noted. Greater growth in the apical inter- 

 nodes and noticeable growth in basal internodes occurred in 

 branch II. Very few showed any growth on the end turned 

 toward the cathode, but growth was considerable though out 

 this series on all ends toward the anode. Branch I in current 

 density j showed the greatest growth of any of the series. The 

 apical internodes in general showed the greatest growth in the 

 series. No apparent general difference in this series as a whole 

 between growth toward anode and cathode was noticeable. 

 But it is important to note that growth on the apical end of 

 every internode in branch I was greater than on the correspond- 

 ing basal end of each piece (cf . fig. 3 above) . 



At thirty-four hours each piece was again drawn freehand, 

 removed, numbered, and finally stained and mounted in the 

 exact order and position in which they had been placed in the 

 trough. Plate 2, A and B, shows the extent of regeneration in 

 the different current densities. The time of appearance of hy- 

 dranths in a control carried parallel to the experiment showed 

 practically the same result as in plate 2, B, branch I. 



