22 



ELEMENTS OF MAMMALIAN ANATOMY. 



tight box with a cloth or absorbent cotton wet with 30 

 c.c. of ether or chloroform. If only the arteries are to 



be injected, the cat may re- 

 main in the box until dead ; 

 but if the veins are also to 

 be injected, it is preferable 

 to use ether for the anes- 

 thetic and then remove the 

 animal to the tray as soon 

 as it is unconscious, and re- 

 flect a portion of skin, ex- 

 posing the external jugular 

 veins (Fig. 3). With the 

 curved forceps thrust be- 

 neath the vein a cord may 

 be pulled through and tied 

 in a loose knot. One-half 

 inch from the latter a 

 second cord should be tied 



FIG. 3. DIAGRAMMATIC View OF 

 OPERATION FOR INJECTION. 



d, Broken line showing course of the 

 carotid artery beneath ; b, string 

 loosely tied; c, transverse vein 

 uniting external jugulars; a, 

 points of curved forceps con- 

 taining string. 



around the vein loosely. An 

 oblique cut (Fig. 4) with the 

 point of the scissors directed 

 caudad is then made in the vein between the cords. The 

 incision should extend about 

 half-way through the vessel. 

 Absorbing the blood with ab- 

 sorbent cotton as it runs from 

 the vessel will prevent clog- 

 ging. If too much ether has 

 not been used, the blood will 

 continue running fifteen min- 

 utes. When it has nearly 

 ceased flowing, the carotid 

 artery must be found by making a slit in the muscle 



FIG. 4. METHOD OF MAKING IN- 

 CISION IN THE CAROTID AR- 

 TERY FOR INJECTION. 



