. [Scientific lectures]. will be seen torapidly absorb water, and swelling, a large and obtuse papilla resem-bling the neck of a bottle is produced, and a seeming empty space isformed in the contents of each spore. As these disappear the wholegranular substance becomes separated by fine lines into five to eightportions each, with a small, faintly colored, empty space in thecenter. These portions are so many zoospores. These are soonexpelled one by one, and soon afterwards begin to move, beingprovided with seeming fins or fringes by which they are enaiiled toswim about like an animalcule : but
. [Scientific lectures]. will be seen torapidly absorb water, and swelling, a large and obtuse papilla resem-bling the neck of a bottle is produced, and a seeming empty space isformed in the contents of each spore. As these disappear the wholegranular substance becomes separated by fine lines into five to eightportions each, with a small, faintly colored, empty space in thecenter. These portions are so many zoospores. These are soonexpelled one by one, and soon afterwards begin to move, beingprovided with seeming fins or fringes by which they are enaiiled toswim about like an animalcule : but they are only buds endowed withmotion, same as many other plants have. These of course arecapable of infecting plants, as we have seen. The prodigal provision of nature is here, as everywhere, especially. Microscopic Revelations. 17 in its lower orders signally manifested, when we are told that theimmense number of zoospores capable of being produced from a singleinfested plant is almost beyond calculation. It is easy for a millionof conidia to be developed from one such plant, each producing fiveto eight zoospores. It can scarcely be considered marvelous that thewhite rust should be so common on plants favorable to its develop-ment, the marvel being rather that any escape. THE POTATO DISEASE. Mould is a word in common use, and aU will tell you what mouldis, yet each will perhaps tell you of a different kind. This very nu-merous family are called Hyphomycetes, that is, fungi that grow bythrowing out delicate threads. Of course there are several distinct groups. To the common eye, unaided by the microscope or observation,mildews, mouldiness, and similar microscopic plants, would be readilyconfounded. But the mildew is a much more highly developed fungus,and though apparently ^s dangerou
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
