PRACTICAL DIRECTIONS. 453 
the larynx (p. 249, and Fig. 105). Dissect all those of one side 
first. ‘The mucosa lining the vestibule and middle portions of the 
laryngeal cavity must be removed. After studying the muscles, 
remove the muscles and entire mucosa by scraping carefully with a 
dull but smooth scalpel, and study the cartilages (Fig. 104). 
III. The trachea and lungs (p. 251, and Fig. 106). The distal 
end of the trachea and lungs may now be removed with the heart 
from the body. The lungs may be inflated with the bellows. The 
bronchi should then be exposed, cleaned, and followed as far as 
possible into the lungs. ‘The heart should be preserved for future 
study. 
DISSECTION OF THE UROGENITAL ORGANS. 
A. £xcretory Organs. « 
_I. Expose the kidney (p. 255, and Fig. 108) by removal of the 
peritoneum and the surrounding fat, taking care not to open the 
capsule of the kidney. In removing the fat from the cranial end do 
not injure the suprarenal body (p. 257), which should be studied. 
2. Open the capsule of the kidney and slice away its ventral wall 
to expose the sinus, After dissecting the contents of the sinus open 
the pelvis and study the papilla. Pass a bristle from the pelvis into 
the ureter. 
3. Make a median section of the kidney parallel to its ventral 
surface and study structure (Fig. 109). 
4. Trace the ureter to the bladder, being careful not to injure 
the vas deferens. Study the bladder and its ligaments, structure of 
its wall, etc. Pass a bristle through the ureter into it and then open 
it to see the openings of the ureter, Trace the neck of the bladder to 
the pubis. 
B. Male Genital Organs. 
1. Study the external genital organs (p. 257). 
2. Carefully remove the integument about the anus and expose 
the external sphincter ani muscle (p. 268, and Fig. 113, 7). Trace 
it to its origin. Remove the integument of the scrotum and dissect 
the intercolumnar fascia, the levator scroti muscle (p. 271, and Fig. 
113, 7), the tunica vaginalis communis, and propria (p. 258). 
3. The testis; the epididymis with great care, especially in 
uncovering the vasa efferentia; the vas deferens and spermatic cord 
(p- 259, and Figs. 110 and 111). . 
4. Follow the cord to the external inguinal ring (p. 259) and 
expose the ring. Dissect off in order from the inguinal canal: (a) 
The external oblique muscle; (4) the internal oblique muscle; (c) 
the transversus. In this way the cord is followed with its tunica 
communis and tunica propria to the internal inguinal ring. 
5. Trace the vas deferens (p. 260, and Fig. 111) within the 
abdominal cavity as far as it can be seen dorsad of the neck of the 
bladder. 
