An Agricultural Experiment Station.



white and fine as frost needles. They grow with the speed which mushrooms have made proverbial, cover the bread, and develop spore threads or spore cups, which in time give rise to new forms. At present a culture of especial interest is a cucumber disease known among the gardeners as "timber rot," variously attributed to a gallfly, to the curculio and to "a diseased constitution," but conclusively proved, by experiment, to be the product of fungous growth.       The cucumber fungus gathers its white threads into sclerotia, black resting bodies which fall off and after a time give rise to tiny spore cups, showing the long, sweeping curves of the cornucopia. Horns of plenty indeed they prove to be, for from one of those microscopic cups, one fourth of an inch in diameter, come millions of spores. A countless number of sacs, mouth up, and covered by the most fragile of membranes, fill the cup to the brim; and every sac contains eight spores. When the sacs are dry, if the finger is drawn lightly across the top of the cup, out come the spores like a puff of powder, ready to fasten on the host plant and begin life over again.
      The black knot has both summer and winter spores, the former appearing in the culture room at present. These conidia, borne on branching threads, were sown on prune gelatine, and have swelled into elliptical forms, producing threads whose tops present the appearance of dark brown velvet. Upon these erect threads appear cone-shaped spores like those sown at first. The winter spores are formed in cavities beneath the checkered surface of the knot.
      Next to the microscope, the favorite instrument of the laboratory is the microtome, used for cutting sections at any angle and at almost any width, filmy sheets one eight-thousandth of an inch in thickness falling smoothly from its knife. In a rear room are to be found the machines for spraying, force pumps in various sizes and patterns.
      The treatment for fungous diseases of plants, as for human diseases of parasitic origin, is largely preventive. Prof. Humphrey says to the farmer and the fruit grower, as the doctor to those of his patients in danger of infection: Keep up the general health. Take care that there is an abundance of food. Remove every tangible trace of disease. Burn infected plants. Here are no hospitals and no quarantine, only Gehenna. Remove the wild plants from roadways and hedges, if subject to the same disease or bearing complementary spores where the fungus is pleomorphic. Disinfect. Preserve perfect cleanliness.
      When extreme measures are to be taken, there are the fungicides, based, for the most part, on sulphate of copper, the spray to be fine and steady, forming upon the plant a copper coat of mail.
      Now arises a panic. Who will dare to eat the cabbages and grapes which have been sprayed with copper. In a bulletin issued by the Secretary of the United States Department of Agriculture, arguments are set forth to prove that an individual must consume twenty-eight heads of cabbage at a sitting or several hundred bushels of grapes, in order to obtain a poisonous dose of arsenic, when Paris green or London purple have been used. On the other hand, the actual gain from spraying, to two hundred and fifty

Radish Growth Experiment

Left: Radishes Grown without Electricity.
Right: Radishes Grown with Electricity.

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