BUREAU OF PLANT INDUSTRY. 299 



potato in cooperation with Prof. L. C. Corbett, Horticulturist, has 

 been begun. 



The occurrence of serious pathological conditions in spinach and 

 cabbage in the vicinity of Norfolk, Va., has led to a study, in coopera- 

 tion with the Office of Truck-Crop Diseases and Sugar-Plant In- 

 vestigations, of the physiological behavior of the plants concerned in 

 relation to their nutrition. This work, now in progress, is conducted 

 by Doctors Hasselbring and Alsberg. In cooperation with the same 

 office a physiological study of the relation of light intensity to sugar 

 production in the beet has been undertaken. 



A physiological laboratory study of the significance of a series of 

 chemical substances in plant growth has been undertaken in the hope 

 of throwing some light on important phases of plant requirements. 

 This rather technical investigation is carried on by the Physiologist 

 in Charge, assisted by Mr. H. H. Bartlett, Chemical Biologist. 



Lemon investigations. — The " sweating " process resorted to in 

 order to color lemons rapidly has been made the subject of a special 

 study. Experience has shown that methods supposed to improve on 

 the old oil-stove device do not serve the purpose. Mr. A. F, Sievers. 

 Chemical Biologist, has shown that heat and humidity are not as im- 

 portant factors in bringing about the desired change as has been sup- 

 posed, the work being done rather by some of the gaseous j^roducts 

 of incomplete combustion, generated by the oil stoves. This con- 

 clusion, if applicable as is now supposed, should have an important 

 bearing on sweat-room construction and operation, quickening the 

 time of coloring, reducing expense for fuel, and diminishing fire 

 risks. 



PLANS FOR FUTURE WORK. 



The same general outline of work will be continued during the 

 ensuing year, in order to yield the best results in the work already 

 under way. 



Drug plants and special proble:\is. — The future work of the drug- 

 plant testing gardens will look largely toward the improvement of 

 the plant stock. The services of a skilled plant breeder will add 

 very greatly to the value of the entire drug-plant work. An exten- 

 sion of the testing work in Texas and the opening of a testing garden 

 in the arid Southwest, in order to test valuable drug plants from 

 similar locations in the Old "World, are matters worthy of attention. 

 In the hop investigations an effort will be made to extend into ad- 

 ditional hop regions the important and very promising improvement 

 work. A thorough laboratory study of hop constituents seems re- 

 quired in order to place this line of work on a sound basis. 



The work on perfumery plants, hitherto carried on chiefly as a 

 laboratory study, seems ripe for a wider development. A promising 

 beginning has been made, and the investigations should now be ex- 

 tended in area and scope in order to test the commercial possibilities 

 of some of tlie more promising crops. 



The projects dealing Avith physiological and fermentation investi- 

 gations are relati\e]y new and are likely to require some little time 

 before they will begin to sliow results. The lemon work will be con- 

 tinued, and tlie coloring of lemons by combustion gases should be 

 tried on a commercial scale in special experimental sweat rooms. 



