Page:Popular Science Monthly Volume 43.djvu/87

 than when it is deep, and the evident opening connects the center of the fruit with the surface.

For its own protection the perfect apple has a continuous layer of skin over its whole surface. The stem has not been removed from its cavity, but remains of its full length, for there is a place naturally provided for its separation from the branch which bore it. Such an apple is the rare exception as found in the barrel. At the market or in the storeroom of the consumer, instead of being without blemish upon the surface, there are small specks as large as a pin-head, or smaller, which dot the skin in patches. A portion of the surface of an apple with these specks is shown three times magnified in Fig. 1. Sometimes one needs to look for a long time to find a fruit entirely free from these specks. Under the compound microscope these dots are resolved into a thin layer of interwoven threads, with their free ends radiating from a central point. This is one of the low forms of plant life belonging to the molds, and grows from microscopic cells called spores, which in the economy of the mold serves the purpose of seeds. These spores are produced in great abundance, and, being carried by the air, alight upon the fruit and there germinate and grow into a colony or speck which is all the time feeding upon the substance obtained from the skin of the apple.

The second defect in apples, as seen in the barrel, is the one known to fruit-dealers as the "scab." To the eye this is recognized by the rough-coated patches, often circular in outline, that are present upon the skin. There may be several of these spots, and, by their borders becoming confluent, one half or less of a fruit may be thus rough coated and more or less dwarfed, making the apple one-sided. This scab is due to a mold which, under the microscope, is as different in its real structure from the specks above mentioned as the two are unlike in general appearance. If it will add anything to the value of this popular article, the botanical name of the species of mold causing the apple scab may be given as Fusicladium dendriticum, Fl. It is as much a distinct