GLOSSARY. 



twelve ; ay-rip, aner, a man). A 

 class of plants in the Linnsean 

 system, having twelve stamens. 



Dol'omite. A variety of inagnesian 

 limestone. 



Dome (Lat. domus, a house). A 

 house ; the external part of a 

 spherical roof. 



Dominical (Lat. (dies) domin'ica, 

 Sunday). Belonging to Sunday ; 

 applied to the letter prefixed in 

 Almanacks to the S,ufcdHys, frora 

 which the days of the week falling 

 on the successive days of past or 

 present years may be computed. 



Dor'sal (Lat. dorsum, the back). 

 Placed on, or belonging to, the 

 back. 



Dorsibran'chiate (Lat. dorsum, the 

 back; Gr. fipayxia, bran'chia, gills;. 

 Having the branchia or breathing 

 organs distributed on the back ; 

 applied to certain mollusca. 



Dorso. (Lat. dorsum, the back). In 

 anatomy, a prefix in compound 

 words signifying connection with, 

 or relation to, the back. 



Double Salt. A salt in which the 

 acid is combined with two different 



Double Stars. Two stars placed so 

 close together that to the naked 

 eye they appear single. 



Doublet. A magnifying glass, con- 

 sisting of a combination of two 

 plano-convex lenses. 



Drastic (Grr. fipaca, draft, I do or act). 

 Acting powerfully ; applied to cer- 

 tain medicines. 



Dropsy (Grr. vSoop, hudor, water ; wj/is, 

 opsis, an appearance). An un- 

 natural collection of watery fluid in 

 any part of the body. 



Drupa'ceous (Drupe). Of the nature 

 of a drupe ; bearing fruit in the 

 form of a drupe. 



Drupe (Gfr. tipvinra, druppa, an over- 

 ripe olive). A pulpy fruit without 

 valves, containing a stone with a 

 kernel, as the peach. 



Du'al (Lat. duo, two). Relating to 

 two ; applied to a form of nouns 

 and verbs in which two persons or 

 things are denoted, as in the Greek 

 and some other languages. 



Duality (Lat. duo, two). The state 

 of being two in number. 



Duct (Lat. duco, I lead). A tube 

 or vessel for conveying a fluid, 

 especially a secretion from a 

 gland. 



Ductile (Lat. duco, I lead). Capable 

 of being drawn out. 



Ductility (Lat. duco, I lead). The 

 property which substances possess 

 of being drawn out. 



Duodecimal (Lat. duod'ecim, twelve). 

 Proceeding in a scale of twelves. 



Duodenary (Lat." duode'ni, twelve). 

 Increasing in a twelvefold pro- 

 portion. 



Duode'num (Lat. duode'ni, twelve). 



* The first portion of the small in- 

 testine ; which, in man, is twelve 

 finger-breadths in length. 



Du'plicate (Lat! duplex," double). 

 Double ; duplicate proportion or 

 ratio is the proportion or ratio of 

 squares. 



Dura Mater (Lat. hard mother : be- 

 cause the other membranes were 

 supposed to proceed from it). The 

 strong fibrous membrane which 

 envelopes the brain and spinal 

 cord. 



Dura'men (Lat. durus, hard). The 

 central or heart wood of an exo- 

 genous tree. 



Dyke. A wall or fence ; in geology, 

 applied to wall-like intrusions of 

 igneous rock which fill up veins 

 and fissures in the stratified 

 system. 



Dynamic (Gr. Swa/jus, du'namis, 

 power). Relating to strength or 

 force. 



Dynamics (Gr. 5wa/j.is, du'namis, 

 power). That part of natural 

 philosophy which investigates the 

 properties of bodies in motion. 



Dynamom'eter(Gr. 8wa/j.is, du'namis, 

 power; p^pov, metron, a measure). 

 An instrument for measuring 

 strength. 



Dysaesthe'sia (Gr. Svs, dus, badly ; 

 al<T0avofj.ai, aisthan' omai, I feel). 

 Impaired power of feeling. 



Dys'entery (Gr. 5us, dus, badly; 

 fi/Tepo^jtii'teron, an intestine). A 

 discharge from the intestines ac- 



