DEM SUPPLEMENT. DIA 



DEMULCENT, a medical application to china, Lat. God from a machine ; said oJ 

 protect any wound or sensitive part from help suddenly rendered in an emer- 

 external irritation. Gum and mucilages gency."(!) 

 generally are demulcents. I DEVITRIFICATION, a peculiar decompoai- 



DENDKITIC or DEXDRITICAL MARKINGS, tion which takes place in glass under the ac- 

 t/ee-like markings on the surface or in the tion of time and certain adverse agencies, 

 internal structure of minerals ; such as the From this cause the glass fragments reco- 

 moss agates, &c. , vered from the ruins of antiquity have be- 



DENTINAL TUBES, tubes radiating from come iridescent and decomposed on their 

 the pulp cavities of teeth. They are supplied surfaces, or dull and without transparency ; 

 by the plasma, or colourless fluid of the in fact partially denitrified. 

 blood in human teeth. DEVONIAN SYSTEM, the middle member 



DENTINE, the chief substance of teeth. i of the great Palteozoic rock formations. It 



DENTITION, the cutting of the teeth. lies under the Carboniferous System, and be- 



DEOBSTRUENT, any medicine which re- tweeii it and the Silurian System, and in- 

 moves obstructions and glandular affec- ( eludes the Old Red Sandstone, Herefordshire 

 tions. | Conglomerates, Russian, Devonian, and Old 



DEODORISERS, certain chemical agents Rhenish greywacke, the Devonshire shales 

 which destroy effluvia or mephitic particles and limestones, and Herefordshire corn 

 suspended in the atmosphere ; as chloride of stones, and the Caithness schists, and Ar- 

 lime, chloride of zinc, (which is Burnett's breath paving stones. 



disinfecting fluid,) carbolic acid, ozone, Con-] DEVONITE, Wavellite, or Hydrargyllite, 

 uy's fluid, charcoal, &c. Fresh ground coffee, from Barnstaple, Devonshire, 

 sprinkled through a sick room, is a very j DIAGOMETEU, an electrical invention for 

 convenient and refreshing form of the char- 1 ascertaining the conducting power of fixed 

 coal disinfectant. oils. It has proved highly useful in detect- 



DEPRESSOR MUSCLES, muscles which ing the adulteration of olive oil, which, it 

 lower the bone on which they act, as distin- pure, has the lowest conducting power of all 

 guished from the companion or Elevator the fixed oils, 

 muscles which raise it. DIALECTICS, a synonym of " metaphy- 



DERM, the true skin or cutit. \ sics," as used by Plato, though more dis- 



EERMOH^MAL, those osseous develop- tinctively applied to the means of conduct- 

 ments by which the fins on the hsemal or ing metaphysical investigations. It is now 

 ventr'l side of the body of fishes are at-: more commonly confined to that part of 

 tached to the dermo-skeleton. j logic which comprehends the rules and 



DEKMONEURAL, those ossified develop- modes of correct reasoning, or logical iuvesti- 

 ments by which the flns on the neural side gation and discussion. 



of the body of fishes are attached to the DIALECTRIC, the characteristic of a body 

 dermo-skeleton. (which allows electricity to act through it; 



DERMO-SKELETON, literally " skiu-skele- [ non-insulating. 



ton." It is the outer and more or less in- 1 DIALOGISM, dialogue so written as to re- 

 durated covering or horny crustaceous or present the conversation of the speakers in 

 osseous integument of most of the inverte- the third person, and not in the first, 

 brate and some of the vertebrate animals, i DIALYPETALOUS, a synonym of " polype- 

 In most cases it supplies the place of a hard talous," but more distinctively applied to- 

 interior framework. those plants which have many distinct pe- 



DESICCATION, such medical applications tals, and not to those with many petal* 

 as dry up the secretions of ulcers, 4c ] united, or gamopetalous, i.e., joined into a 



DESMINE, a foliated variety of zeolite. j monopetalous corolla. 



DETERGENTS, medical applications which I DIAMAGNETIC, the magnetic character- 

 cleanse sores and remove viscid matters. istic of those bodies which are repelled by 



DETRUSION, (literally " thrusting aside,") either pole of a magnet, as distinguished 

 a term used to express that pressure of one from bodies attracted by either pole, 

 body against another which tends to thrust | DIAMIDES, neutral chemical bodies ob- 

 it from its place. To " thrust out of place," tained from two atoms of ammonia by re- 

 " out-thrust," or "outward thrust," are all placing successively thirds of the hydrogen, 

 more, or less forms or varieties of detrusion. by negative radicals. 



DEUS EX MACHINA, a term now some- DIAMINES, alkaloids obtained from two 

 what indefinitely used, which originated atoms of ammonia by replacing thirds of the 

 with the ancient drama, in which by the aid hydrogen successively by ethylene and other 

 of a machine the gods were sometimes re- diatomic radicals. 



presented as flying in the air. This being DIAPHANOUS, synonymous with " trans- 

 frequently resorted to without adequate re- lucent," but not transparent. 

 quirement passed at last into a proverb, sig- ; DIAPHORESIS, perspiration, 

 nifying the unnecessary resort to supernatu- 1 DIAPHORETIC ANTIMONY, an old name for 

 ral agency. In a modern work the following antimoniate of potassa and peroxide of an- 

 meaning is loosely given: "Dent ex Ma- timony. 

 784 



