138 ANATOMICAL TECHNOLOGY. 



Barrel. The barrel of the syringe is the large cylindrical part in which the piston fits. 

 The injecting mass is drawn into it by pulling the piston in the direction of the handle. 



Canula, 



Handle. jj& Leather packed piston. 



FIG. 35. WHITE-METAL SYRINGE WITH TOP UNSCREWED AND PISTON 

 REMOVED ; x .3. 



Canula. The canula is the smaller part which serves to connect the syringe with the 

 object to be injected. 



Handle. The handle is a continuation of the piston. It projects from the barrel, and 

 by it the piston is moved. 



Piston. The piston of a syringe is within the barrel. Its end should be packed with 

 leather, as shown in the figure, so that it will fit very closely. 



Canula or Nozzle. The canula serves to 

 connect the syringe with the object to be in- 

 jected. The end should be cut off obliquely. 

 fl It is then like a wedge, and may be inserted 

 TJ into the vessel much more easily than one 



cut squarely off. 



r The caliber of the canula should be as 

 II great as can be put into the vessel to be in- 

 jected. For plaster injections ( 341) the 

 FIG. 36. CANUL^E ; x .6. canula should not be less than 1 mm. at its 



narrowest point. - 



A. Metal canula with lateral arms at the end next the syringe, and a slight shoulder 

 at the small end. 



B. A glass canula cut off obliquely at its small end. 

 C. A glass tube drawn out for two canulae. 



340. To prepare glass cairalae, take a glass tube about 6 mm. 

 in diameter and from 8-10 cm. in length, and heat its middle evenly 

 in a Bunsen flame. When the glass is softened, draw the two ends 

 apart until the tube is sufficiently reduced in caliber in the middle ; 

 then after cooling make a fine scratch with a file as shown in C, and 

 the two may be broken apart. When separated, grind the end first 

 on a fine file with water to make it oblique as in A and B, and 

 finally on the fine oil stone to make it smooth. Heat the larger end 

 in the flame to round the sharp edges. 



