1912.] PUBLIC DOCUMENT — No. 31. 71 



Besides the correspoiideiicc relating- to seed work and the 

 control of diseases, we arc constantly called npou to answer let- 

 ters of a very special and technical nature. These inquiries 

 come from everywhere and cover a multitude of subjects, such 

 as electricity and plant growth, electrical injury to trees, illumi- 

 nating and other gases, chemical treatment of reservoirs, mod- 

 ern tree surgery, court decisions regarding shade trees, different 

 stimulating factors in the growing of plants, requests for advice 

 in regard to devices for the extermination of various pests, etc. 



