The microscope : its history, construction, and application, being a familiar introduction to the use of the instrument, and the study of microscopical science / by Jabez Hogg.

  • Hogg, Jabez, 1817-1899.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: The microscope : its history, construction, and application, being a familiar introduction to the use of the instrument, and the study of microscopical science / by Jabez Hogg. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    to the animal kingdom, Phylloxera vastatrix. This oi'diimi appears on the grape in the form of greyish filaments, terminating in an enlarged head, whicli contains an agglomeration of spores, not free or in a chaplet, as in Aspergillns (Fig. 273). These spores when ripe burst from the capsule as fine dust, and are diffused by the air in all directions, thus spreading the disease far and away. Another of the parasitic moulds, Peronospora viticola, is a kind of mildew, differing from oi'dium. The hyphse penetrate more deeply than that of oidium. On the upper surface of the leaf brown patches appear; these branch out and ramify as seen in the potato- fungus, P. infestans (Fig. 274). The parasite destroys the tissue of the leaf, and it withers and dies. There are other well- known parasites, the black-rot, Phoma- uvicola, belonging to the Ascomycetes. This appears in early shoots in the form of round black spots, and gradually spreads over leaves and young fruit. This same rot, one year, devastated the American vineyards. Cereals, wheats and grasses, suffer from other well-known forms of microscopic fungi termed rusts and smuts, which cover the blades or infect the full ear of the fruit. The name given indicates their colour, and these belong, for the most part, to the genus Uredo and the family of the Basidiomycetes. They have no endogenous spores but as many as four forms of exogenous. This is also the case with wheat and barley, whereby they are distinguished as Uredo or Puccinia graminis (see Figs. 273 and 274, and Plate I., Nos. 19 and 22, rig. ■275.—Fungi, Moulds. a. Clustered Spores, Gonatohotrys simiAex ; I). Spore of Fuccinia coronata, the mildew of grapes ; c. Barley smut ; d. Pticcinia allium ; e. Penicillium glaucum ; in. Ixodesfarince, found in damaged flour together with smut.