SPE 



SPI 



posite the seed much more regularly, 

 and at an equal depth." 



SOW THISTLES. Composite 

 plants of the genus Sonchus. They 

 are smooth perennials, with a milky 

 juice. 



SPADE. A well-known garden 

 implement. The spading of land pro- 

 duces the best results from the thor- 

 ough loosening and great depth to 

 which the soil is stirred. Astonish- 

 ing crops have been obtained on small 

 lots by using the spade for wheat and 

 root culture ; but the expense is the 

 great drawback. 



SPADIX. A form of inflorescence, 

 m which the flowers are arranged 

 around a fleshy rachis, and enclosed 

 within a kind of bract called a spathe, 

 as in palms and araceous plants. The 

 Indian turnip is an instance. 



SPANISH NEEDLES. Annual 

 weeds of the genus BideTis, the seeds 

 of which adhere to the skin of ani- 

 mals and clothes. 



SPAN WORMS. The caterpillars 

 called geometers, loopers, or canker- 

 worms. See Canker-worm. The fe- 

 male of the prefect insects are inca- 

 pable of flight, and crawl up trees to 

 lay their eggs ; various contrivances 

 have, therefore, been adopted to hin- 

 der them passing, such as a rope of 

 straw bound round the trunk, a layer 

 of tar spread on paper and fastened 

 round, or lead and tin troughs con- 

 taining oil, water, or other prepara- 

 tions, have been afli.xed to the trunk 

 with great advantage. 



SPASM. A cramp. Rubbing the 

 skin with turpentine, when it is of 

 the external muscles, often alleviates 

 the pain. 



SPATHE. See Spadix. 



SPAVIN. See Horse, Di.irasrs of. 



SPAYING. The operation of ex- 

 tracting the ovaries of the females of 

 ditTerent kinds of animals, as sows, 

 heifers, mares, &,c., in order to pre- 

 vent any future conception, and pro- 

 mote fattening. 



SPEAR GRASS. A name given 

 to the Poa pratcnsis. 



SPEAR.MINT. Common green 

 mint : also the weed Mentha tenuis. 



SPECIES. In natural history, an 



individual separated from others of a 

 genus by certain slight but permanent 

 characters. 



SPECIFIC GRAVITY. See Grav- 

 ity. 



SPECTRUM. An image, usually 

 applied to the image of the sun seen 

 through a prism, and which consists 

 of seven colours. 



SPECULU.M. A reflector or mir- 

 ror of metal. 



SPEEDWELL. The genus Fcron- 

 ica, perennial plants, ol'ten with beau- 

 tiful spikes of blue flowers. 



SPELT. Spelter wheat. See 

 Wheat. 



SPERMATIC ANIMALCULES. 

 Minute, thread-like animalcules found 

 in the secretion of the testes. 



SPERMATIC CORD. The col- 

 lection of blood-vessels passing from 

 the abdomen to the testes. 



S P E R M I D I U M. The same as 

 akenium, a small seed vessel resem- 

 bling a seed. 



SPHACELUS. Mortification, gan- 

 grene. 



SPH AGNU.M. A genus of mosses 

 growing in bogs, and forming a great 

 deal of the peat. 



SPHENOID BONE. A bone in 

 the base of the skull. 



SPHINCTER (from ff^r/;ra), / 

 close). The name of muscles which 

 close the natural openings of the 

 bodv. 



SPICE WOOD, or BUSH. Lau- 

 rus benzoin. Benjamin bush, fever 

 bush. An indigenous shrub, four to 

 ten feet high, the wood of which yields 

 an aromatic smell. It grows on damp 

 places. 



SPIGEL. Fennel. 



SPIKE. An inflorescence, in which 

 ' the flowers are sessile upon an up- 

 , right stem. 



[ SPINACH. Spinaciaoleracea. An 

 ' annual of the family Chenopodiacem. 

 Varieties : Large round-leaved, broad- 

 leaved Savoy, Holland. The New 

 I Zealand, which is a superior vegeta- 

 ble, is very large and running : it is 

 j the Tetras^ona ezpansa. The seeds 

 are planted in hills six feet apart, 

 three to the hill, in May ; twenty hills 

 i supply a family. 



743 



