64 DEPARTMENTAL KEPORTS. 



of a new method of growing the organisms which, instead of causing 

 them to become weaker and weaker until they become a mere parasite, 

 enables them to so increase in virility that they fix five times as much 

 nitrogen as those normally found in nature. Extensive practical 

 experiments were inaugurated to determine the foregoing facts, the 

 work being carried on at the Arlington Farm, located near Washing- 

 ton, on the Flats, rnd in the Department greenhouses. 



The great value of this nitrogen work can hardly be estimated. 

 There are annually imported into the United States from 180,000 to 

 200,000 tons of nitrate of soda, with a value of from $5,000,000 to 

 $6,000,000, an average of about $30 per ton. "By careful and con- 

 servative estimates it can be shown that on every acre devoted to the 

 growing of leguminous crops the tubercle" organisms enable these 

 plants to add from $8 to $10 per acre in nitrogenous fertilizer. In many 

 cases the presence or absence of proper organisms is the element 

 which decides the failure or success of the crop. 



In the work on algfe the discovery and practical application of a 

 method of preventing the contamination of cress l)eds may be noted. 

 This work was begun too late last fall to give as satisfactory results as 

 would have been obtained had it been commenced before the alga3 

 had such a start. Algas play an important part also in the matter of 

 contamination of water supplies. Filtration, instead of benefiting, 

 only aggravates the conditions, and the constant complaints of the 

 public health officers and authorities in charge have made it necessary 

 to make an earnest effort to prevent such contamination. p:ngineers 

 and chemists have tried in vain to secure a remedy, and it now 

 remains to be seen whether or not we niay be able to solve the ques- 

 tion. Encouraging results have already been obtained and have 

 aroused much interest on the part of boards of health and similar 

 organizations. 



WORK OF PACIFIC COAST LABORATORY. 



During the year the lines of work on the Pacific coast have consid 

 erably broadened, and, as heretofore, have been carried on, under the 

 direction of the Pathologist and Physiologist, by Mr. Newton B. Pierce. 



Plant breeding and selection.— The development of new forms l)y 

 breeding and selection has been made a special feature of this woi-k. 

 Particuhif attention has l)een given to the improvement of the walnut, 

 chestnut, and grape. The grape-ci-ossing experiments, which have 

 been conducted during several years, are neai-ing a stage of practical 

 utility. Hundreds of seedlings, the results of crosses among raisin 

 and table grapes, have recently been transplanted from nursery iorm 

 in the San Joaquin Valley to open vineyard form in southein Cali- 

 fornia. They are now under favorable vineyard conditions, so far as 

 soil, water, and distance of setting are concerned, and many of them 

 have already set fruit. It is hoped that this season's crop will be suf- 

 ficient to demonstrate the value of the vines and that enough wood 

 may be produced to warrant the distribution of cuttings within the 

 next year. 



Plant-introduction work. — During the year it has become jnore 

 obvious than ever that Pacific coast conditions of climate, soil, irriga- 

 tion, elevation, etc., are requisites which, if they could be drawn 

 upon, would greatly add to the plant-introduction work of the Depart- 

 ment. To facilitate such investigations a limited tract of desirable 



