invention. Derricks and tents are used in this gas treatment, and it solves many difficulties in the way of using washes and the spray system on the citrus fruit trees. The city of Riverside owns several complete sets of the necessary apparatus, and rents at a nominal rate to fruit-growers, who hire operators and furnish the necessary chemicals. Since this is not a technical treatise, however, I must refer students of the perpetual struggle going on in California between the orchardist and his insect enemies to the publications of the Agricultural Department of the State University and of the State Board of Horticulture. Here, in thousands of pages, the story is told in every detail. There is not only an active warfare going on against insect foes, but various predaceous and parasitic insects that destroy dangerous species have been called to the aid of the horticulturist.
In conclusion, one must ask, "How goes the fight?" The statistics of the fruit industry answer this question. The cost of destroying insect pests has become a permanent item of expense, the results of which are increased profits. Care and management of orchards now include preparation of the soil; selection of varieties adapted to the place; planting and culture of the trees; pruning, according to different systems for different species and localities; the use of special fertilizers, and the destruction of noxious insect life. The various coccids that infest the California orchard valleys are only to be found in dangerous numbers upon the orchards of the careless or the ignorant fruit-growers. Their multiplication is readily and safely checked on as large a scale as desired, and at a cost paid many times over by the increased crop. Sometimes, for several seasons and over large districts, the coccids disappear, but they return, and renewed expenditures of time and skill are necessary to conquer them again. The expense lessens, however, and the certainty of success increases, year after year as the fruit-grower becomes a specialist. Does this appear too difficult? It is the same old demand for intellect, inherent in the order of things. Horticulture in every division is a science as well as an art, and it more and more amply rewards the technical skill of the well-equipped specialist.