Page:The American Cyclopædia (1879) Volume XV.djvu/308

 296 SQUILL Its medicinal effects are diuretic and expecto- rant, and in large doses emetic and purgative. It is largely employed as an expectorant in do- mestic practice, for croup and similar affec- tions of children. Vinegar or dilute acetic acid is found the best solvent of the active principles of squill ; the drug is first exhausted by the acid, and the vinegar of squill thus ob- t-iiiicd is made into a sirup with sugar. SQUILL (squilla, Fabr.), a genus of crusta- ceans of the division stomapoda, so called from having the feet placed around the mouth. The body is elongated and generally slender, the head distinct from the thorax, the carapace leaving uncovered four of the thoracic rings, and the abdomen terminating in a wide caudal fin of several plates adapted for swimming. The antennae of the first segment of the body are long, ending in three many-jointed fila- ments, cannot be bent under the head, and are inserted below the eyes near the median line ; the antennae of the second segment are shorter, more external, having at the base a large ciliated plate, and terminate in a single many-jointed filament ; the eyes are at the end of movable appendages. The mouth is toward the posterior third of the carapace, and has an upper and under lip, a pair of mandibles, and two pairs of jaw feet arranged around it ; the third pair of feet are prehensile, strong, bent back on themselves, serrated and spined, and used very much like the first pair of feet in the soothsay- er (mantis) ; the next three pairs are directed for- ward, applied against the buc- cal apparatus, and inserted close together, with a wide, rounded, ciliated plate at the end ; the last three thoracic limbs are slen- der, with styli- f orm process and ciliated, the seg- ments to which they are attached resembling those of the abdomen. Mostof the rings of the body are complete, very nearly equal, and movable on each the carapace is nearly quadrilateral, longitudinally divided by two more or less dis- tinct grooves; the first five abdominal rings have large false feet, to the posterior part of the base of which are attached the respira- tory organs in the shape of floating, ramified Squill (Squilla mantis). SQUINTING and fringed gills, which are kept constantly in motion. The heart extends almost the length of the abdomen and thorax, a little dilated an- teriorly, sending off lateral branches to each ring ; the venous sinuses in which the blood is collected before going to the gills are very large ; the stomach advances far into the head. There are many species, all marine, most abun- dant in the tropics, but occasionally seen as far north as the English channel ; they are usually met with far from shore and in deep water ; they swim rapidly ; they are voracious and carnivorous. The best known species is the 8. mantis (Fabr.), 6 or 7 in. long, pale yellow- ish gray, found in the Mediterranean. SQUINTING (Lat. strabismus), a deformity con- sisting in a want of parallelism between the visual axes of the eyes. Except in cases where it is caused by paralysis, spasmodic or hydrop- ical affections, or irritation of the brain, it is not a disease, and is not accompanied with pain. Ophthalmic surgeons notice three degrees of squinting: 1, where there is but'a slight con- vergence or divergence from the normal axis, such as is ordinarily called a "cast of the eye ;" 2, where the inclination is strongly marked, but less than half the cornea is thrown under the eyelid or within the orbit, which is the most frequent variety ; 3, where the cornea is nearly or quite thrown under the eyelid or within the orbit, common among those who are born blind, but rare in the case of those who can see. The surgeons also distinguish it accord- ing to the departure from the normal axis ; as convergent, where the pupil is drawn toward the nose ; divergent, where it is drawn toward the outer corner of the eye ; ascendent, where it is drawn upward; and descendent, where it is drawn downward. Of these, the conver- gent form is by far the most frequent, and next in order the divergent and ascendent. The descendent is the rarest of all. Squinting may also be double or single as one or both eyes are affected ; it may be congenital, i. <?., existing from birth, or accidental, occurring from accident or improper treatment of the eye ; the former is rare. It may be also con- tinuous, or rarely intermittent. When not due to one of the causes mentioned above, it de- pends in a large majority of cases on parallel rays of light not focusing on the retina. To correct this the eye turns in, as in so doing the power of accommodation is increased, because the same nerve which supplies the internal rectus also supplies the muscle of accommoda- tion. (See EYE.) The treatment prior to 1839 consisted in attempting by various methods to strengthen the weaker muscles, bandaging the normal eye, and compelling the constant use of the other ; or by the use of goggles, specta- cles, &c., in which all except the centre was opaque. In 1838 Stromeyer described the op- eration of dividing one of the recti muscles, but without having tried it on the living sub- ject. In 1839 Dieffenbach, an eminent sur- geon of Berlin, performed it successfully, and