320 A. J. Goldfarb 



EFFECTS DUE TO REGIONAL DIFFERENCES^ 



Experiment 2. Is the tendency to regenerate polyps more 

 strongly developed in one region of the stem than in another, or 

 is the same average number produced in all regions of the same 

 size ? Pieces from a series of large stems were compared and 

 the number of polyps produced in each was separately estimated, 

 viz: (i) The basal end of a stem, about one-tenth of the whole 

 stem, (2) the basal half of a second stem, (3) an entire third stem, 

 (4) and the two halves of this stem separately considered. 



No regeneration occurred on the small basal pieces until the 

 seventh day after amputation. Even then very few polyps ap- 

 peared. The basal halves regenerated 17 per cent, the entire 

 stems much more, namely, 36 per cent. More striking, however, 

 is the difference in the regenerative power of the basal and distal 

 halves of entire stems, for 70 per cent regenerate on distal halves, 

 but 3 per cent on basal halves. The figures for six days reinforce 

 these conclusions. Smaller stems, however, do not reveal this 

 sharp contrast in the regeneration of the two halves of stems. 



Experiment j. Similar stems were cut into three nearly equal 

 parts. The distal thirds regenerated two days after amputation; 

 most of the middle pieces did not regenerate till the third day, and 

 the basal pieces, not till the third or fourth day. The question of 



^Some very interesting facts in this connection are given by Gast and Godlewski in Die Regula- 

 tionserscheinungen bei Pennaria cavolinii, Archiv f. Ent., Bd. i6, 1903. 



