254 TOCAB.ULAKY. 



T. 



Teleosts (or Tel-EOSTEi). The name of tliat sub-class of fislies 

 whicli embraces the great majority of living species, and so 

 designated (by Johannes Miiller) on account of the ossified 

 condition of the skeleton in all the representatives of the 

 ^j.Q^jp_ Theodore Gill. 



Teratol'ogy. a treatise on monsters. 



Ter'tiary. Third ; of the third formation. In geology, a 

 series of strata, more recent than the chalk, consisting of 

 sandstones, clay beds, limestones, and frequently containing 

 numerous fossils, a few of which are identical with existing 

 species. It has been divided into Eocene, Miocene, and Pli- 

 ocene, which sea. Dana. 



Tikctu'ra Myrrhs. (Tincture of Myrrh.) Tonic, deobstruent 

 (removing obstructions), antiseptic (opposed to putrefaction), 

 and detergent. It is chiefly used in gargles, and is applied 

 to foul ulcers, spongy gums, &c. 



Tissue. By this term, in anatomy, is meant the various parts 

 which, by their union, form the organs, and are, as it were, 

 their anatomical elements. ' Histological anatomy ' is the 

 anatomy of the tissues, which are the seat of the investiga- 

 tions of the pathological anatomist. The best division, in- 

 deed, of diseases would be according to the tissues mainly 

 implicated. 



Tox'ODON. A gigantic, pachydermatous quadruped, now ex- 

 tinct, having teeth bent like a bow. Brande. 



Transuda'tion. (To sweat.) The passage of a fluid through 

 the tissue of any organ, wliich may collect in small drops on 

 the opposite surface, or evaporate from it. 



Trephine'. The instrument which has replaced the trepan in 

 some countries. It consists of a simple, cylindrical saw, with 

 a handle placed transversely, like that of a gimlet; from the 

 center of the circle described by the saw a sharp little per- 

 forator, called the center-pin, projects. The center-pin is 

 capable of being removed, at the surgeon's option, by means 

 of a key. It is used to fix the instrument until the teeth of 

 the saw have made a groove sufficiently deep for it to work 

 steadily. ' The pin must then be removed. Sometimes the 

 pin is made to slide up and down, and to be fixed in any 

 position, by means of a screw. 



