10 o EXPERDIEXT STATION. [Jan. 



organic matters which are known as "growth accessory sub- 

 stances." An electrometric method for the determination of 

 carbon dioxide, which was developed last year, has been em- 

 ployed in the investigation. The results of the investigation, 

 together with the method used, w'ill be ready for publication 

 in the near future. There has also been a study made of the 

 microbial decomposition of cellulose. 



Physiological Ixvestigatioxs. 

 Department of Botany. 



Project 1. "Optimum conditions of light for plant response." 



Assistant Professor Clark. 



This project was started in 1915 under the Adams fund. At 

 present the work is divided into two parts: "A study of the 

 light requirements of field and garden crops," and "Study of 

 the effect of ultra-violet light on plant grow^th." The investi- 

 gation is carried on both in the greenhouse and out of doors, 

 and by natural as well as by artificial light. 



Project 15. "Plant stimulation by formaldehyde." 



Owing to Dr. Chapman's resignation from the station staff, 

 no work has as yet been done on this project. 



Department of Pomology. 



Project 1. "Study of the interrelation of stock and scion in 

 apples." 



Professor Shaw. 



This project was begun in 1912, and the main orchard set 

 in 1915 and 191G. A new orchard of 450 trees was set in the 

 spring of 1921 from the surplus trees on known roots in the 

 nurseries, in which it is planned to investigate the nature of 

 the graft union between certain varieties. In resetting these 

 trees the relation of crown gall to different varieties was 

 studied and data collected showing that each root variety 

 exhibits a special form of the gall, and that some varieties are 

 highly resistant to the disease. No reports on this project 

 have as yet been published. 



