GLOSSARY. 



171 



Spher'oid (Gr. ffQcupa, sphaira, a 

 "ball ; eiSos, eidos, form). Re- 

 sembling a sphere ; a body ap- 

 proaching a sphere in form, but 

 not perfectly globular ; the result 

 of the revolution of an ellipse 

 about one of its axes. 



Spherom'eter (Gr. <r(paipa, sphaira, a 

 sphere; fj-e-rpov, met 'ron, a measure). 

 An instrument for measuring the di- 

 mensions of a sphere. 



Spher'ule (Gr. a-tyaipa, sphaira, a 

 ball ; ule, denoting smallness). A 

 little sphere or globular body. 



Sphinc'ter (Gr. cr<f>iyyo>, sphingo, I 

 bind). A name given to circular 

 muscles surrounding the orifices of 

 organs or parts of the body. 



Spnygmom'eter (Gr. <r<j>try/ios, sphug- 

 inos, the pulse ; /ierpov, met'ron, 

 & measure). An instrument for 

 counting the pulsations of an artery 

 by rendering the action of the 

 pulse visible, and measuring its 

 strength. 



Spica (Lat. an ear of corn). In 

 surgery, a kind of bandage, so 

 called from its turns being thought 

 to resemble the arrangement of the 

 ears of corn on the stem. 



Spic'ular (Lat. spic'ulum, a dart). 

 Resembling a dart ; having sharp 

 points. 



Spic'ula (Lat. spic'ulum) a dart). In 

 botany, a spikelet. 



Spic'ulum (Lat. a dart). In surgery, 

 a small pointed piece of bone or 

 other hard matter. 



Spike (Lat. spica, an ear of corn). 

 In botany, a form of inflorescence 

 in which sessile flowers are placed 

 on a simple peduncle or stem, as 

 in the wheat and lavender. 



Spikelet. In botany, a small spike, 

 or cluster of flowers, as in grasses. 



Spina Bif'ida (Lat. cleft spine). A 

 diseased state in which part of the 

 bones of the spine a.re deficient, so 

 that the membranes of the chord 

 project in the form of a tumour. 



Spinal (Lat. spina, the spine). Be- 

 longing to the spine or back-bone. 

 Spinal Chord or Marrow. The part 

 cf the nervous system contained in 

 the canal of the vertebral column. 



Spinal System of Nerves. The 

 nerves which convey impressions 

 to and from the spinal cord espe- 

 cially. 



Spine (Lat. spina, a thorn). A 

 thorn ; an abortive branch with a 

 hard sharp point ; in anatomy, the 

 vertebral column or back-bone ; in 

 zoology, a thin pointed spike. 



Spines'cent (Lat. spina, a thorn). 

 Becoming thorny ; bearing spines. 



Spinif' erous (Lat. spina, a thorn ; 

 fer'o, I bear). Producing spines or 

 thorns. 



Spi'niform (Lat. spina, a thorn ; 

 forma, shape). Like a spine or 

 thorn. 



Spin'neret (Sax. spinnan, to make 

 yarn). The pointed tubes with 

 which spiders weave their webs. 



Spi'nous (Lat. spina, a spine or 

 thorn). Having spines ; in ana- 

 tomy, projecting like a spine. 



Spi'racle (Lat. spiro, I breathe). A 

 breathing hole ; applied to the 

 external openings of the air-tubes 

 of insects. 



Spiral (Gr. ffireipa, speira, anything 

 wound round). Winding round a 

 fixed point, and at the same time 

 constantly receding, as the main- 

 spring of a watch ; winding round 

 a cylinder, and at the same time 

 advancing ; in architecture, a curve 

 winding round a cone or spire. 



Spiral Vessels. In botany, fine 

 transparent membranous tubes, 

 with one or more spiral fibres 

 coiled up in their interior. 



Spirit Level. An instrument for de- 

 termining a plane parallel to the 

 horizon, consisting of a tube of 

 glass nearly filled with spirits of 

 wine or distilled water, and her- 

 metically sealed, so that, when it 

 is placed in a horizontal position, 

 the bubble of air in the liquid 

 stands exactly in the centre of the 

 tube. 



Spirom'eter (Lat. spiro, I breathe ; 

 Gr. fiSTpov, met'ron, a measure). 

 An instrument for measuring the 

 quantity of air exhaled from the 

 lungs, and thereby determining the 

 capacity of the chest. 



