180 



W. RALPH JONES 



does factor merely by wetting, and so starting the activity of the 

 peripheral cells sooner than those of the interior? 



Experiment 6. The cotyledons of dried peas were mutilated by 

 filing in several ways : 



(a) The peripheral layer of the entire convex side was removed, 

 leaving only internal cells exposed on the convex face, and periph- 

 eral cells exposed on the flat face (fig. 2, the shaded portion 

 denotes the part removed). 



(6) A slab was filed from the convex side, leaving some periph- 

 eral and some internal cells exposed on the convex face, the flat 

 face remaining normal (fig. 3). 



Fig. (i 



Fie. 2-5 



Fig. 7 



(c) As 6, but with the entire peripheral layer of the flat face 

 also removed (fig. 4). 



(d) Two deep notches were' cut into the convex face, thus 

 exposing some of the internal cells (fig. 5) . 



These dry mutilated cotyledons were then placed on wet filter 

 paper in a moist chamber, and kept in darkness. Other seeds, 

 mutilated in the same ways, were soaked in water before placing 

 in the moist chamber. Unmutilated cotyledons were used as 

 control. Rough examinations were made from time to time by 

 means of hand sections stained with iodine, and material was also 

 fixed in chrom-acetic acid, imbedded in paraffin, sectioned, and 

 stained with gentian violet and orange-G. The results were the 



