Page:The New International Encyclopædia 1st ed. v. 01.djvu/753

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APHASIA.
645
APHONIA.

lies may oe acenmiJanied by aphasia. The treat- ment isthat of the underlying disease. Consult: Gould and Pyle, Ct/clopevdia of Medicine and Surgcnj (Philadelphia, 1900).

A'PHEK. (1) A place near Sidon {.Tosh. xiii. 4), havinsr a temple to Ashtoreth : probably the modern Aphka at the source of Nahr Ibra- him. (2) A city belonging to the tribe of Asher (Josh. xix. 30; .Judges i. 31). (3) A stronghold near llegiddo, where the Philistines assembled their army for the battles of Gilboa ( 1 Sam. xxi.x. 1) and Ebenezer (I. Sam. iv. 1), and from which Benhadad and Hazael (I. ICings xx. 2G; II. Kings xiii. 17) made their attacks upon Samaria. It is probably identical with Apukn in the annals ot Tehutimose III. (1503-1449).

APHE’LION (Gk. dwd, apo, away + 7)io!, /if/ios, the sun). That point in the elliptical orbit of a planet which is most remote from the sun. The opposite jjoint, or that nearest to the sun, is styled the perihelion. At the former point, the swiftness of the planet's motion is least, and begins to increase; at the latter, it is greatest, and begins to decrease. This irregular- it}' of motion is most remarkable in comets, since their orbits deviate most from the circle. See Ap.sides.

APH'ELIOT'ROPISM, or Negative Heliotropism. That form of sensitiveness by virtue of which plant organs direct their axes away from the source of incident light. Certain roots show this reaction to light; e.g., those of mustard seedlings. It is seen also in the ten- drils of Bignonia capreolata. See Heliotropism.

A'PHID (probably from Gk. d^tiSTis, aphei- di'K, unsparing, from d, a, priv. -|- ^elSea-ffai, pheldesthai. to spare). A bug of the family Aphididse, commonly knovn as plant-lice, which live either free on the foliage, bark, or roots of plants, or inclosed in galls. They nourish themselves on the sap of their plant-hosts, which they suck up through a long, slender rostrum. They are minute, the largest being one-fourth of an inch long. The color is usually green or brown, and the shape like that of a pear. Most of the forms that live on the roots of plants underground have neither compound eyes nor ocelli. Several forms secrete a cottony, protective coat. At the posterior end of the abdomen of most aphids there are two tubes, or perhaps mere perforations, through which a sweet liquid, called honey-dew, comes out, a drop at a time. Upon this the young feed for the first day or two. The flow may be so abundant as to render the stems and leaves sticky, or, when the wind is blowing, the liquid may even fall to the ground in a sweet spray. The leaves and bark are not infrequently covered by fungi, which thrive on the honey-dew, and insects, especially ants, are attracted to it. The ants protect from year to year the makers of this food supply, and also feed eagerly upon the honey-dew itself, and cherish the aphids for its sake. See Ant.

Dimorphism, or even polymorphism, is very common among aphids. Thus the forms that live on the roots of plants and those that live on their foliage possess certain structural dill'orences. When all the foliage forms perish, the under- ground ones may make good the loss, as is the case with the Delaware peach species. Again, the sexes may be winged or wingless, and the females may bring forth the young alive, or they may lay eggs. From the eggs parthcnogenetic females alone hatch. These produce living young for many generations. At times of drought or on the approach of winter, males, usually winged, appear, which fertilize the eggs of the wingless females. These eggs liatch in the following spring into the "stem mothers," and the cycle begins again. It has been estimated that "the progeny of a single "stem mother" of the cot- tony apple aphis may be one quintillion in a season. See Hop-LocsE.

Aphids stunt or kill growing tips, weaken the entire tree by impoverishing it of sap, and pro- duce galls and other abnormal growths. Entire crops of cereals may be destroyed by them. Let- tuce, beans, indeed nearly all vegetables, sufTor from their ravages, and house-plants are particu- larly infested by them. The price of hops from year to year varies largely according to the abun- d.ance of the hop-vine aphids ; and to this fam- ily belongs also the grape-vine pest (Phyllox- era) of Europe. Inundation of the ground in cold weather is fatal to this pest. Carbon bisul- phide is also used. In the greenhouse, tohncco smoke, soapsuds, and ladybird beetles are etl'ect- ive checks. Young fruit and shade trees in the open may also be treated with soapsuds, as well as with hydrocyanic-acid gas applied under closed tents. Birds and spiders feed on plant- lice, ichneumon and syrphus-fly larvie destroy great numbers of them, both the adults and the young of all sorts of ladybird beetles feed ravenously upon thera, and they are persecuted by deadly parasites. Indeed, were it not for the insect foes of plant-lice, there would be little or no vegetiition. The winter eggs of aphids may endure any amount of cold, but a cold, wet spell in the spring is fatal to the newly hatched aphid. See Scale Insect.s, and the names of various trees and plants upon which they prey; and of works on injurious insects and economic entomology, especially for the United States, see Thomas, Eighth Report State Entomolo- gist of Illinois (Springtield, 1879) : and for Europe, Buckton. Monograph of British Aphides, Ray Society (London, 1879-83) .

APHIS-LION. The larva of a lace-winged fly, especially of the family HemerobiidiP, which feed on plant lice. It is closely related to the ant-lions and golden-eyed flies. See Lacewing.

APHO'NIA (Gk. i<t>avla, from d, a, priv. + (puf-^, phone, voice, sound). The term used in medicine to signify a more or less complete loss of voice. It is altogether distinct from mutism, in which it is impossible to form articulate sounds, and in most cases the voice is not entirely gone, but only more or less lost or suppressed. The voice is essentially produced by three distinct agents — viz. ( 1 ) the expiration of air, (2) the opening of the glottis, and (3) the tension of the vocal cords ; and hence anything interfering with expiration, or with the functions of the glottis and vocal cords, may cause aphonia. Thus, it may result from paralysis of the respiratory muscles, from pulmonary emphysema, and sometimes from pneumonia ; or it may be caused by diseases of the larj-nx. as chronic laryngitis, oedema of the glottis, polypus, etc. ; or by pressure on the larynx caused by abscesses, vegetations, and any kind of morbid growth; or it may be traced tc some functional or organic disturbance of the inferior vocal cords. Thus, the muscular fibres which act on these cords may become affected in acute laryngitis bv extension