REPORT OF THE SECRETARY. 57 



have been materially improved. An investigation relative to the 

 toxic effect on fruit trees of certain elements, notably copper and 

 arsenic, which may accumulate in the soil as the result of using com- 

 pounds containing these substances as sprays, has been under way for 

 the past two years and is now ])ractically completed and the results 

 are ready for collation and publication. The results of this work 

 will be of the greatest value to fruit growers and agriculturists in 

 determining w^hether or not permanent injury to vegetation through 

 the medium of the soil is to be feared from repeated application of 

 poisonous insecticides and fungicides. 



CATTIiE FOODS AND GRAINS. 



Five hundred and four samples of cattle foods and grains were ex- 

 amined in the course of the year in connection with the enforcement 

 of the food and drugs act. Of these, 89 were reported to the Board 

 of Food and Drug Inspection as adulterated or misbranded. The 

 work on cattle foods and grains has also included the examination 

 of various samples for the solving of such economic problems as the 

 feeding value of forage and range crops and improved methods of 

 handling corn after harvesting. 



LEATHER, PAPER, ROSIN, AND TURPENTINE. 



Work has been done on bookbinding, carriage, automobile, and 

 furniture leathers showing that the same harmful practices prevalent 

 in the tanning of sole and other heavy leathers exist among the pro- 

 ducers of these leathers. Experiments have been continued on the 

 utilization of waste long-leaf pine for making paper and the re- 

 covery of wood turpentine, rosin oils, and wood creosote. Standard, 

 nonfading type samples of rosin have been devised and are expected 

 to promote the correct grading of rosin and at the same time to prove 

 more economical to the official graders. The work on production of 

 wood turpentine, its refining, its value as a paint and varnish thinner, 

 and its effect on the workmen using it in paints has been continued, 

 and the information thus obtained will be used in new experiments. 



EXAMINATION OF CONTRACT SUPPLIES. 



The investigations of rubber goods and paint materials have been 

 continued with good results. Attention has been given to platinum 

 laboratory utensils and enamel-ware cooking utensils. Improved 

 methods have been devised for testing inks and typewriter ribbons. 

 The samples examined for other departments of the Government 

 during the year number 2,442, in addition to 1,800 pieces of apparatus 

 examined for the Bureau of Chemistry. 



