NEW CELL FOR^L\TIONS IN PLANTS 283 



tubes from the reservoir. This was partially accomplished thru the 

 use of bolts and wing-nuts in place of the springs used by Dr. Rumbold. 

 It only succeeded with fairly mature stems. In order to take advantage 

 of the greater activity of young stems, another method was devised. 

 A h>TDodermic syringe was used to introduce the fluid, generally inta 

 the pith cavity. After the solution was injected, the needle punctures 

 were covered with grafting wax. As an indicator of the path taken by 

 the injected fluid Anilin Black was used for some of the injections. For 

 the other chemicals used, see page 285. The plants used in the experi- 

 ments were Phytolacca decandra, Heliantlms anmms, Ricimis sp., and 

 Polygonum Sieboldii. The plants were allowed varying lengths of time 

 for such growths as might result from the injections to mature, and then 

 were cut down. After cutting, the specimens were brought in to the 

 laboratory and either sectioned fresh or preserved in alcohol for subse- 

 quent examination. Mounts of the Anihn Black injections were made 

 immediately, care being taken not to extract the dye. Most of the other 

 specimens were sectioned under alcohol, a few were embedded in Celloidin, 

 and still fewer in Parafiin. Safranin and Methyl Green was the com- 

 bination of dyes used on the unembedded material, while Safranin and 

 Delafield's Haematoxyhn served for the Celloidin and Paraffin prepa- 

 rations. 



Summary of Experiments on Herbaceous Plants 



The work on Phytolacca was begun early in July, 1916, and was 

 largely in the nature of preliminary tests to determine the best methods 

 to use on the Helianthus and Ricinus material, which was not yet ready. 

 The gravity-method injections (2) yielded Httle, but the hypodermic 

 needle gave some interesting results. The injections of Anilin Black 

 showed that the fluid passed up thru the protoxylem region. This is 

 what might have been expected, for the protoxylem region formed by 

 far the largest part of the conducting tissue at the time of the injection. 

 The only histological effect of this substance was to decrease the rapidity 

 of xylem lignification for a few centimeters up the stem and to reduce 

 the number of pitted vessels formed. 



Picric Acid was the only other substance injected into Phytolacca, and 

 as a strong solution, in small quantities. If this solution had been in- 

 jected in large amounts into an internodal cavity as the weaker solutions 

 were in later experiments, the poisonous effect would have been extreme. 

 Internodal cavities were absent from stems of the size and age used. 

 The shoots were not as young as those used in the other plants. The 



