Page:The American Cyclopædia (1879) Volume XV.djvu/632

 ; 604 TEAES with obscure brown spots, and the same blue and white in the wings as in the male. It is found throughout eastern North America to the Rocky mountains, is abundant about the mouths of the Mississippi in winter, and is less hardy than the green-winged species. TEARS, the limpid, colorless, slightly saline secretion of the lachrymal glands, continually poured out in quantity sufficient to bathe the surface of the eyes, tosecure the easy and free motion of the lids, and to wash off any irrita- ting particles from their sensitive membrane. The lachrymal belong to the aggregated glands, or those in which the vesicles or acini are arranged in lobules ; there is one at the upper, external, and anterior part of each orbit, in a depression of the frontal bone, in relation with the external rectus muscle, resting behind on a fatty areolar tissue ; each gland is of the size of a small almond, reddish white, flattened, and enveloped in a fibre-cellular capsule ; the secretion is poured out by six or seven trunks opening within the upper lid. At the inner angle of the eyes, in both lids, are two very narrow, always open apertures, the lachrymal puncta, in the middle of a slightly prominent tubercle, about 1 line from the inner junction of the lids ; they are opposite each other, the lower turned up and the upper down, and both outward and backward. Through these open- ings the tears are conveyed by the lachrymal ducts in each lid to the lachrymal sac, at the inner angle of each eye, in the bony groove between the lachrymal bone and the ascending process of the superior maxillary ; it is a small membranous sac, opening below into the nasal duct, which conveys the tears into the nose beneath the inferior turbinated bone. At the inner angle of the lids, in front of the globe and behind the lachrymal puncta, is a small reddish tubercle, pyramidal, with the summit turned forward and outward ; this is the lachry- mal caruncle, and consists of a mass of small mucous follicles, covered by the conjunctiva, which forms in front and to the outside a semi- lunar fold, called the nictitating membrane ; this is rudimentary in man, but remarkably de- veloped in birds. The act of crying, generally accompanying an increased secretion of tears, as far as the movements of respiration are concerned, is very nearly the same as that of laughing, though occasioned by a contrary emo- tion ; the expiratory muscles are in more or less violent convulsive movement, sending out the breath in a series of jerks, accompanied by well known sounds ; in children the act is some- times continued almost to the complete emp- tying of the chest of air, to the great dismay of parents, but the necessity of breathing is always stronger than the convulsive muscular movements. Moderate excitement, whether of joy, tenderness, or grief, increases greatly the quantity of the tears, though the secretion is checked by violent emotions ; in intense grief the tears do not flow, the restoration of the secretion being a sign of moderated sorrow, TEASEL and itself affording relief by the resumption of nervous action. The sensory, emotional, or instinctive ganglia, situated at the base of the brain, to a certain extent independent of the will, in intense grief become congested, and the flow of tears is the natural method for their relief ; hence the danger of cerebral dis- turbance from long continued tearless grief. Considering their size, there are no other glands which ordinarily can so increase the amount of their secretion as the lachrymal ; the quantity is sometimes very great, and very easily stim- ulated ; the shedding of tears is also conta- gious. The lachrymal puncta may be closed, causing the tears to flow over the cheeks, for which the remedy is dilatation by fine probes. When the nasal duct is obstructed, the eye is watery and the corresponding nostril dry, the sac forming a small tumor at the side of the nose; the sac also may be inflamed, with pain, tenderness, swelling, and feverish symptoms ; this may end in suppuration, and an external opening, constituting lachrymal fistula, requi- ring the restoration of the obliterated duct by styles of different materials. TEASEL (A. S. tmsel, from tcesan, to tease), the ripened flower heads of dipsacus fullonum^ used for raising a nap upon woollen cloths. The genus dipsacus (Gr. di-tyeiv, to thirst, sup- posed to refer to the cups formed by the united leaves in some species, which hold water) is the representative of a small family, the dipsacea, which is so closely related to the composites that in a systematic arrangement it is placed next to that family. Like the composites, the teasel family have their flowers in dense heads, but their antfliers are not united and the seeds have albumen. In the teasel itself, of which there are 'about a dozen old-world species, the plants are biennial or perennial, with coarse, deeply toothed, opposite, rough leaves; the branches are terminated by an oblong head, consisting of small flowers, each in the axil of a bract, which appears as a strong scale when the seeds are ripe. The wild teasel (D. sylves- tris) is sparingly introduced, and is found in the older states as a roadside weed; it is from 2 to 6 ft. high, and its numerous heads of pale purple flowers, with a large involucre at their base, make it a conspicuous and not inelegant plant; the bracts to the heads terminate in a long straight point ; it should be treated as an intruder. The teasel of commerce, or fullers' teasel, though bearing the specific name given above, is generally supposed to have originated from the wild teasel, from which it differs in having a longer head with a shorter involucre ; the bracts are much stiffer, and have hooked points. These heads, when ripe, are about 2J- in. long and 1 in. in diameter, and clothed with regular, strong, sharp, recurved hooks; they are an important article of commerce, and in some countries of cultivation ; considerable quantities are produced in England, but the chief supply is from Holland and France. The teasel has now and then been cultivated in