SHADOW 



1320 



SHELL 



Shadow {shad'-o) [ME., schadowe, shadow]. A 

 phantom-cell, or skeletonized blood-cell, formed by 

 the removal of the hemoglobin from a red cor- 

 puscle. S.-test. See Retinoscopy. 



Shaft [ME., shaft, shaft]. The trunk of any columnar 

 mass, especially the diaphysis of a long bone. 



Shakes (shaks) [ME., shaken, to shake]. A popular 

 designation for Ague. 



Shaking [ska' -king) [ME., shaken, to shake]. A 

 passive Swedish movement used in the treatment of 

 nervous affections. S. Cure, the treatment of disease 

 by a shaking or vibratory movement, advocated by 

 Charcot in paralysis agitans, by means of a vibrating 

 arm-chair. S. Palsy. See Paralysis agitans. 



Shale {shdl) [G. , schale,& scale]. Clay with a fissile 

 structure. S. Naphtha. See Photogene. S. Oil. 

 See Benzine. 



Shampoo (sham-poo') [Hind. ,tshampna, shampoo]. I. 

 Synonym of Massage. 2. To lather, rub, or wash the 

 head. 



Shampooing {sham-poo' -ing) [shampoo]. The per- 

 formance of massage with the application of a liniment 

 or other medicinal substance, and also in connection 

 with the Turkish bath. 



Shank [ME., shanke, the bone of the leg]. The leg 

 from the knee to the ankle ; the tibia or shin-bone. 



Shark [napxapoc, jagged]. One of a large group of 

 . sea-fishes constituting the order, Squalidcz. S.-oil, 

 an oil prepared from the livers of various species of 

 shark. It is the lightest of the fixed oils, the specific 

 gravity ranging from .865 to .876. It is used in the 

 adulteration of cod-liver oil and for tanning. 



Sharpey's Perforating Fibers. Transverse or perpen- 

 dicular periosteal fibers, most numerous in the superfi- 

 cial lamellae of spongy bones ; they are also present 



Sharpey's Perforating Fibers. (From Stirling.) 



in the interstitial lamellae of other bones, transfixing 

 the lamellae. Kolliker recognized a smaller, soft, 

 uncalcified, and a larger, partly calcified, variety. 



Shavegrass {shav'-gras). See Scouring Push. 



Shaven-beard Appearance. A peculiar appearance 

 of the enlarged intestinal glands in typhoid fever. 

 They are dark-red or reddish-gray in color, and marked 

 with fine white striations. 



Shearing {shlr'-ing) [ME., sheren, to clip]. I. The 

 overlapping of the cranial bones of the fetus during its 

 passage through the pelvis. 2. In biology, the result 

 of attrition of the incisorial region of the lower jaw 

 against the front of the upper jaw in aged persons who 

 have lost their teeth. Shearing takes place in propor- 

 tion as the upper jaw at its anterior arc is beaked, and 

 when present the articular surface of the condyloid 

 process is invariably at the anterior part. (Harrison 

 Allen.) 



Shears (shirz) [ME., sheres, shears]. A large pair of 

 scissors. S., Bandage. Strong shears for cutting 

 bandages, usually bent at an angle. 



Sheath (shlth) [ME., shethe, sheath]. An envelop; 

 a covering. In anatomy, applied to the coverings of 

 arteries, muscles, nerves, fascia, etc. S., Arach- 



noidean, a delicate partition lying between the pial 

 sheath and the dural sheath of the optic nerve. S., 

 Axis-cylinder. See Huxley's Layer. S., Capil- 

 lary, or S., Circumvascular, a wide lymphatic 

 tube surrounding some of the smallest blood-vc 

 S., Cellular. See Epineurium. S., Cortical, the 

 bast-bundles. S., Dentinal, the structure lining the 

 dentinal canals. S., Dural, a strong fibrous mem- 

 brane forming the external investment of the optic 

 nerve. See Dura. S., Femoral. See Femoral. 

 S., Fibril, a sheath formed of connective-tissue 

 fibrils and surrounding individual nerve-fibers. S. 

 of Henle, an attenuated extension of the peri- 

 neurium investing the fibers composing funiculi of a 

 nerve-trunk ; it consists of a delicate fibrous en- 

 velop lined with endothelial plates, which in some 

 cases alone represent the entire sheath. S., Hux- 

 ley's. See Huxley's Layer. S., Lamellar. See 

 Perineurium. S., Leaf. See Vagina. S. of 

 Mauthner, a protoplasmic investing membrane be- 

 neath the neurilemma and the nodes of Ranvier, 

 passing inward to separate the myelin from the axis- 

 cylinder. S., Medullary, the myelin-sheath sur- 

 rounding the axis-cylinder. S., Myelin. Medul- 

 lary Sheath and Neurilemma. S., Nerve. See 

 Perineurium. S., Neumann's. See S. , Dentinal. 

 S., Perivascular. See S., Capillary. S., Pial, 

 the extension of the pia which closely invests the 

 surface of the optic nerve. See Pia. S., Primi- 

 tive. See Neurilemma. S., Root. See Root- 

 sheath. S. of Schwann. See Neurilemma. S., 

 Synovial, a synovial membrane which lines the 

 cavity attached to a bone and through which a 

 tendon glides. S., Tangential, the fibro-cellular 

 sheath surrounding the carotids. 



Shed [ME., sheden, to shed]. To throw off. 



Shedding [shed' -ing) [ME., sheden, to shed]. Throw- 

 ing off. S. Teeth, trie teeth of the first dentition ; the 

 term is also applied to the loss of the first or temporary 

 set of teeth. 



Sheep (shep) [ME., sheep, sheep]. A ruminant mam- 

 mal of the family Bovida and genus Ovis. S.-bug. 

 See Argas tholozani in Parasites {Animal), Tat 

 S. -cough. See Hoose. Also Strongylus jilaria , Ru- 

 dolphi, under Parasites [Animal), Table of . S. Gad- 

 fly. See Oestrus ovis, L., under Parasites {A?/: 

 Table of . S. -laurel. See Kalmia. S. -louse. 

 Trichodectis sphcerocephahis, Nitzsch, in Parasites (Ani- 

 mal), Table of. S.-pest, the sheep-tick. S.-pox, 

 a contagious pustular disease of sheep similar to cow- 

 pox. See Ovination. S. -sorrel, the leaves of com- 

 mon sorrel, Rumex acetosclla. Their acidity is due 

 to potassium oxalate and tartrate. They are refrige- 

 rant and diuretic, and are useful as an antiscorbutic. 

 Dose of the infusion ad lib., of the fld. ext. zj-ij. 

 Unof. S.-tick. See Melophagus ovinus, under 

 sites {Animal), Table of S.s' Wool, a fine grtdel 

 of Bahama and Florida sponge. S.s'-wool Fat. 

 See Suint and Lanolin. 



Sheet {shit) [ME., shete, sheet]. A large pi' 

 linen or cotton used as bed-clothing. S.-bath. i 

 Bath. S., Draw, a sheet so folded as to !«<• \ 

 or removed, from beneath the patient with tin 

 inconvenience. 



Sheffield Grinders' Rot. Synonym of Pneumon 

 osis. 



Shell {slid) [AS., seel; D., scliel, shell]. In bii 

 I. A hard, bony, calcareous, chitinous or silicious 

 outer covering; a scale, husk, test, lorica, cara 

 elytron. 2. A thin or hollow structure, as tin 

 ear. S. -follicle, the integumentary sac cont 

 the primitive shell of a mollusc. S. -gland, (") th< 



