138 THE MONTHLY BULLETIN. 



the amount necessary to permanently sterilize the soil along roadways, 

 etc., has been determined, but is under study. A liberal application 

 of Formula 3 diluted one to ten or one to twenty might be tried where 

 injury to the soil is of no consideration. 



"DONT'S." 



Don't handle or use arsenicals or corrosive chemicals without first 

 familiarizing yourself with their properties and behavior. 



Don't purchase arsenicals without a reliable guarantee of the per- 

 centage of arsenic. 



Don't be fooled by secret preparations or use them without knowl- 

 edge of their composition. 



Don't use too small a vessel for dissolving arsenic. 



Don't inhale the steam from boiling arsenicals. 



Don't breathe any of the fumes if any arsenical is accidently spilled 

 upon a hot stove or into a fire. 



Don't boil water, sugar, and white arsenic with any of the solvents 

 for arsenic. 



Don't breathe any of the dust caused by handling powdered arsen- 

 icals or caustic soda. 



Don 't make large quantities of stock solution in a closed room. 



Don't splash the solutions. 



Don't spray forage plants with poisons without taking j)recautions 

 that they will not be eaten by live stock. 



Don't breathe the smoke when burning brush which has been treated 

 with a heavy application of arsenicals. 



Don't put any soluble arsenical upon the foliage or roots of trees 

 or cultivated crops. 



Don't use arsenic too liberally. 



SOME RESULTS OF EXPERIMENTS. 



Sufficient progress has been made in the experiments to w^arrant the 

 following statements: 



1. Under certain conditions the leaves and stems of plants are able 

 10 absorb enough poison from a single spraying to kill their roots to a 

 depth of several feet. 



2. Arsenical herbicides as generally used in California have been too 

 concentrated to produce the best results. 



3. Strong arsenicals liberally sprinkled upon agricultural land are 

 apt to injure the soil. Two experimental plots of one square yard each, 

 heavily infested with morning-glory, were each uniformly sprinkled 

 with a solution made by diluting one fluid ounce of the stock solution 

 as given in Formula 3 to one gallon. Each plot, therefore, received 

 one-half ounce of arsenic trioxide. From the time of treatment to the 

 present writing, a period of five months, all plant growth has been 

 prevented, with the exception of a few morning-glory plants, notwith- 

 standing the washing effect of the heavy winter rains. The growth 

 of the- morning-glory and native weeds and grasses, however, is lux- 

 uriant in the adjoining untreated field. The soil in these experiments 

 was apparently injured by the application of one-half ounce of arsenic 

 trioxide per square yard. 



