NEW CELL FORMATIONS IN PLANTS 285 



from a cambium that generally originated from the second layer of corti- 

 cal cells inside of the epidermis. It extended for two or more centimeters 

 on all sides of the wound. 



The work on Polygonum Sieboldii was started at the suggestion of 

 Dr. Macfarlane in order that advantage might be taken of its rapid 

 growth by forcing in the greenhouses, and that injections might be made 

 at a time of year when the plants outside were still dormant. About 

 thirty experiments were so conducted, from January 1917 on. The 

 first experiments outdoors were made on the 16th of April 1917, and of 

 these fifty were eventually set up, as well as twenty controls. 



Stages have been obtained showing the formation of the cambium 

 developed from the pith cells, with the laying down of xylem by this 

 cambium. The points shown in the other experiments:— cell-outgrowths 

 into the pith cavity, local proliferations of cortical cells, etc., have been 

 duplicated. A new feature appearing here for the first time in the 

 writer's experiments is the formation of xylem from the inner cortex, 

 which has already been reported by Schilberszky to follow his operations 

 on Phaseolus. This in the present experiments only appeared when 

 the treatment had been unusually severe. 



The work on Helianthiis, Phytolacca and Ricinus was limited to the 

 injection of Anilin Black and Picric Acid. The choice of Picric Acid 

 was made because it was thought to have been especially effective in Dr. 

 Rumbold's injections. The chemicals used on Polygonum were:— Anilin 

 Black, Picric Acid, Ammonium Hydrate, Lithium Carbonate, Copper 

 Sulphate, Sodium Carbonate, Potassium Chlorate. Ammonium Car- 

 bonate, Chloroform and Urea, all in aqueous solutions and in most 

 cases in two or more dilutions. All injections were made with the 

 hypodermic syringe into the internodal cavity. 



The action of the different chemicals differed only in rapidity and 

 extent. The writer could trace no specificity in action, beyond the fact 

 that some failed to produce the internal pith proliferations. There is 

 here given a summary of the reactions in some of the more important 

 groups of Polygonum injections : — 



Distilled Water. Both simple proHferations into the cavity and 

 a pith cambium were present. No formation of xylem from the pith 

 cambium was evident. 



Chloroform Water. There was here an advanced formation of 

 the pith cambium following the injection of water saturated with Chloro- 

 form. 



