DEPARTMENT OF BOTANICAL RESEARCH. 57 



The year has been characterized by the most cordial cooperation on 

 the part of a number of institutions, some of which have borne a share 

 of the expense of researches carried on at the departmental laboratories, 

 and cash donations to defray the expense of certain researches have 

 been received. 



EQUIPMENT. 



The cages for testing environic effects on plants and beetles having 

 become unsafe and unsuitable, a new suite was constructed, with 

 bases of brick and cement and tops of cypress suitable for holding 

 netting or glass, and temperature-control apparatus has been installed 

 in several experimental units. The most notable addition to the 

 equipment consisted of the new laboratory for phytochemical research. 



The investigations of the last four years on the relation of light to 

 organisms have clearly revealed the fact that the most hopeful point 

 of attack of these highly complex problems is the study of the chemical 

 changes produced by light. Such a study naturally requires chemical 

 and physico-chemical investigations of a highly specialized natlire. In 

 accordance with these requirements a new laboratory was designed 

 for the study of the chemical and physiological effects of hght, and this 

 was completed in November 1914. 



The building, 50 by 28 feet, is of stone; the inner walls are pressed 

 brick. It contains two laboratories equipped with water, gas, direct- 

 current and alternating-current electricity, vacuum, air-pressure, and 

 large fume hoods. There are also a small shop and preparation 

 room, a machine room for vacuum and pressure pump, 4-horsepower 

 motor generator set, water-still, etc., a study, and a capacious attic 

 used for storage and in connection with experiments on the roof. One 

 side of the main laboratory, 23 by 25 feet, is arranged and fully 

 equipped for chemical work; the other side is devoted to work with 

 plants, microscopic- work table, and the thermostatic apparatus for the 

 investigations of the effect of sunlight on respiration. The other 

 laboratory is a photo-chemical dark-room for work with artificial 

 sources of light as well as sunlight, spectroscope and polariscope work, 

 etc. On the roof there is an insolation deck, 30 by 15 feet, covered with 

 sheet lead; this is virtually an open laboratory affording excellent 

 facilities for special chemical and physiological experimentation with 

 sunlight. 



PHOTOLYSIS. RESPIRATION. HYDRATATION. AND GROWTH. 



The Mechanism and Conditions of Growth, by D. T. MacDougal. 



Auxographic records of the growth rates of seedhngs of corn, wheat, 



and opuntia at the Desert and Coastal Laboratories include continuous 



tracings of the growth expansion of a large number of plants during 



the entire development of leaves and of segments of flattened stems. 



