28 MASS. EXPERIMENT STATION BULLETIN 327 



paper. This insulating procedure prevents the roots from going through the 

 pot into the ground. 



A cheap metal container made for use in the home or greenhouse has been 

 tested. When the metal is properly protected with paint, rusting is prevented 

 and the life of the container is prolonged. Satisfactory growth was obtained 

 with and without drainage holes. 



The nutrient problem of maintaining the vigor of a plant in any type of 

 plant container seems solved by using plant nutrient material carrying nitrogen 

 in an organic form. This not only sustains growth, but also keeps a balance 

 between foliage and flowers. 



DEPARTMENT OF CHEMISTRY 



W. S. Ritchie in Charge 



The Effect of Fertilizer and Cultural Treatment on the Composition 

 of Havana Seed Tobacco. (E. B. Holland.) Samples of the web from the 

 various grades of leaf of the 1934 crop were prepared for analysis as a supple- 

 mentary measure and are held for examination if needed. 



The Copper, Iron, Manganese, and Iodine Content of Fruits and 

 Vegetables Used as Human Foods. (E. B. Holland, C. P. Jones, and W. S. 

 Ritchie.) Twenty-six new samples bought on the market have been added 

 to the number collected in previous years. The analytical work has been 

 continued on these samples representing the more common fruits and vege- 

 tables. The determination of iron, copper, manganese, phosphorus, total ash, 

 and acid soluble and insoluble ash has been completed on fifty-six samples. 



Absorption by Food Plants of Chemical Elements of Importance in 

 Human Physiology and Nutrition. (E. B. Holland, W. S. Ritchie, and W. 

 S. Eisenmenger. ) Beets, carrots, onions, lettuce, and spinach were raised 

 under special fertilization during the past season to determine the ability of 

 these crops to assimilate copper, iron, manganese, and iodine. Thirty samples 

 were secured and added to the number available for analysis under the pre- 

 ceding project. 



Cooperative Analytical Service. (The Department.) This includes co- 

 operative investigations with the Waltham Field Station on the effect of storage 

 on the composition of celery, the cause and prevention of chlorosis on gardenias, 

 and the actual source of injury to greenhouse plants from burned sulfur. 



Additional samples of normal rutabagas and those affected by "dark centers" 

 were analyzed. 



The effect of automobile mileage on the composition of lubricating oil was 

 also studied. 



Bordeaux mixture 5-5-50 and basic copper sulfate with Wyo-Jel were applied 

 to potatoes in cooperative field tests. There was practically no blight, and 

 Bordeaux proved a better repellent for aphids, flea beetles, and leafhoppers 

 than the basic sulfate mixture. 



Testing Analytical Methods. (The Department.) Analytical methods 

 have received considerable attention due to the interference of some vitiating 

 product in a few samples. Complete oxidation by wet combustion was found 

 difficult in some cases and a clear colorless solution did not prove a safe guide. 



The study of the methods for determining iodine in vegetative organic 



