THE MONTHLY BULLETIN. 133 



of scientific plant-breeding, representing as it must additional knowl- 

 edge of the processes of evolution and heredity, may become of practi- 

 cal service; and any result of practical plant-breeding, involving as it 

 does extensive experiments with plants, may prove to be of great scien- 

 tific importance. They are mutually stimulating, and both are neces- 

 sary to the most rapid development of knowledge. 



It is the proper balance between the two that must be mainlaim-d. 

 The physical needs of man, great as they may be, must never obscure 

 the intellectual needs of man ; especially as the trained intellect is the 

 speediest agent in meeting pliysical need. On the other liand. the intel- 

 lectual needs of man, noble as they may be, must never lose sight of 

 the fact that the speediest results are obtained by the enormous increase 

 of experimental work under the pressure of physical necessity. 



The motto of botany and of agriculture, therefore, is the same : A 

 practice based on science, and a science that extends and illuminates 

 practice. 



HERBICIDE INVESTIGATIONS. 



By Geo. P. Gray, Insecticide Laboratory, University of California, Berkeley, Cal. 



The State Agricultural Experiment Station is conducting an investi- 

 gation to determine the most suitable chemical for use in the destruction 

 of weeds. Tests are being made of the various chemicals which have 

 been suggested for this purpose and some new- compounds are being 

 tried out. Analyses are also being made of the commercial prepara- 

 tions which are sold as weed destroyers. 



The proper strength of the chemical to be used, the time of year to 

 obtain the best results, and the effect on the soil are all questions of 

 great importance and are under investigation. These questions should 

 be answered by conducting carefully planned experiments before the 

 general use of any chemical as an herbicide should be either condemned 

 or recommended. 



Recommendations for the use of arsenic in destroying weeds are so 

 frequently made in the papers, and proprietary weed killers are being 

 so widely advertised that it seems a word of warning should be issued 

 against their indiscriminate use. In many instances weed destroyers 

 of unknown composition and home-made preparations of arsenic and 

 other chemicals are carelessly handled with little thought of the danger 

 of poisoning persons and animals, and of possible ill effects on the soil 

 if used too liberally. 



DANGER IN USING ARSENIC FOR DESTRUCTION OF WEEDS. 



The arsenical herbicides are usually made by dissolving commercial 

 white arsenic (arsenic trioxide) in caustic soda, or sal soda, and 

 Avater. When dissolved in this manner, a corrosive chemical is formed, 

 known as sodium arsenite, which is even more poisonous than the orig- 

 inal white arsenic. This is not only poisonous to the higher animals 

 and insects, but also acts as a violent poison to practically all plant life. 



Harmless Appearance: When pure sodium arsenite is dissolved 

 in water, it makes a colorless and oderless solution, having only a 



