234 VOCABULARY. 



cells are examples. They are mainly compossd of protoplasm 

 and contain in their interior bodies called nuclei, in wbich 

 are still smaller ones called nucleoli. T. E. Satterthwaite. 



Correla'tion (mutual relation) of Forces (otherwise called 

 'Transmutation of Force or Energy'). A phrase of recent 

 origin, employed to express the theory that any one of the 

 various forms of physical force may be converted into one or 

 more of the other forms. The cardinal point in this theory 

 is the doctrine of heat and its relation to other agents, espe- 

 cially to mechanical motion. For example, the heat mani- 

 fested when we rub two flat surfaces briskly against each 

 other, is only our own muscular motion checked by the fric- 

 tion, and changed thereby into the heat wdiich the surfaces 

 reveal. On the other hand, this muscular motion is only the 

 beat of our bodily frame expending itself in this way. In 

 either case the energy has not been annihilated, but only 

 transferred, and appears in a new form. 



Johnson's N. U. Cyc, article revised by J. H. Seelye. 



Crura. The plural of cms, ' a leg.' Applied to some parts of 

 the body, from their resemblance to legs or roots, as the 

 ' crura cerebri,' ' crura cerebelli,' &c. 



Cul-de-sac. Any bag-shaped cavity, tubular vessel, or organ, 

 open only at one end. Dana. 



D. 



Dental Canal. The bony canals through which the vessels 



and nerves pass to the interior of the teeth. 

 Dental Cavity. A cavity in the interior of the teeth, in which 



is situate the dental pulp. (More properly the pulpal cavity.) 

 Dental Pulp. The pultaceous substance, of a reddish-gray 



color, very soft and sensible, which fills the cavity of the 



teeth. It is well supplied with capillary vessels. 

 Dentig'erous. Tooth-carrying, as dentigerous cysts ; one 



containing teeth. 

 Dermal. Relating or belonging to the skin. 

 Dermatoid or Dermoid. Tliat which is similar to the skin. 



This name is given to diflerent tissues which resemble the 



skin. The dura mater has been so called by some. 

 Deter'gents. Medicines wdiich possess the power to deterge 



or cleanse parts, as wounds, ulcers, &c. 



