MINUTE, KOD-SIIAPED PARASITES. 255 



Tro'car. An instrument used for evacuating fluids from cavi- 

 ties, particularly in ascites (serous fluid in the abdomen, or, 

 more properly, dropsy of the peritoneum), hydrocele (watery 

 tumors;, &c. A trocar consists of a perforator, or stylet, and 

 a canula. The canula is so adapted to the x^erforator that, 

 when the puncture is made, both enter the wound with facil- 

 ity ; the perforator being- then withdrawn, the fluid escapes 

 through the canula. 



Tubercle. Miliary tubercles are muiute, bright, rounded, trans- 

 lucent particles, called granula, granulations, kc. When 

 they coalesce, forming larger bodies and undergo a change of 

 color they are known as crude or yellow tubercles. As age 

 advances, the center is apt to be occupied by a giant cell, a 

 large multinucleated body, whose boundaries and processes 

 are hard to define, because they shade oflT gradually into the 

 surrounding tissue. They are the result of an inflammatory 

 process, because they can be produced by the introduction 

 of mechanical irritants. In some instances we have reason 

 to believe miliary tubercles may become organized and a 

 cure result. Tuberculosis is hereditary, and there is some 

 good evidence to prove it is contagious ; it is also inoculable, 

 and " breeds true," always producing its kind, if it produces 

 anything, but it has not been satisfactorily proved to have a 

 specific virus. T. E. Satterthwcdte. 



(Dr. Koch of Berlin says (1882) tuberculosis is caused by 

 minute, rod-shaped parasites (bacilli) ; that he has inoculated 

 animals with them, producing tuberculosis; that he has 

 dried the sputum of phthisical patients for two months and 

 has bred the parasites artificially for several generations 

 without their losing the power of inoculation ; that when 

 the sputum is dried the air is infected ; that bovine and hu 

 man tuberculosis are identical ; that tuberculosis can be 

 given to man by the vaUk (perhaps flesh also) of tuberculous 

 cows. The parasites are about _i_.^th of an inch in length.) 



Tu^^IC. An envelop ; as the tunic of the eye, stomach, bladder. 



TuRGES'CENCE. Superabundance of humors in a part. ' Tur- 

 gescence of bile * was formerly used to denote the passage of 

 that fluid into the stomach and its discharge by vomiting. 



Tympanites. A flatulent distention of the belly ; tympany. 

 Also inflammation of the lining membrane of the middle ear. 



