Excerpt from Studies on the Downy Mildew of Onions, and the Causal Organism, Peronospora Destructor (Berk.) CasparyFresh spores for use in these tests were obtained by spraying an infected plant in the greenhouse with water and placing it under a bell glass. For the night. On the following morning the fresh conidia that had been formed during the night were brought into suspension by dipping the mildewed leaves into water. In this manner only fresh mature spores were obtained, and they were protected from desiccation since they were not exposed for any length Of time to the air. Drops of the suspension were placed on clean microscope slides in moist cham bers and these were placed in incubators at different temperatures. The necessary apparatus for the tests was placed in the incubators the night before, so that it would be at the temperature at which the spores were to be tested.Distilled water was used at first as a suspension medium for the spores, but, since many of the spores were ruptured owing to high osmotic pressure, it was necessary to find a more favorable medium. A test in which the germination of the spores in distilled water, in lake water, and in physiological salt solution, was compared, showed lake water to be a suitable medium. The results of the test are given i.i table 4.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.