CHAPTER X. 



DISSECTION OF THE ABDOMEN. 



Before this part can be begun in the male subject, the dissection of 

 the perinseum (Chapter IX.) must be completed. 



THE ABDOMINAL WALL, 



Position. — The subject should be placed on the middle line of its 

 back, or slightly inclined to one side, its limbs being drawn upwards and 

 outwards by ropes and pulleys. 



The Mammary Glands, or the Udder. It is convenient to describe 

 here these glands, since their dissection must precede that of the 

 abdominal wall. They are organs peculiar to the female, occupying the 

 position of the scrotum in the male. As regards their function, they 

 may be viewed as an accessory part of the reproductive system, secreting 

 the milk upon which the young animal subsists for some time after 

 birth. It is only during the period of lactation that they become fully 

 developed, and therefore a subject suited for the satisfactory display 

 of their structure seldom presents itself in the dissecting-room. 



The glands are two in nvimber, and are placed side by side on the 

 middle line of the abdominal wall, in front of the pubes. They form 

 here a single mass, with a wide and shallow mesial furrow between 

 them. The term " udder " is used to include both glands. From the 

 most prominent part of each, the mamilla, teat, or nijjple, projects. 

 This has the form of a short, flattened cone. Its free extremity is 

 perforated by two or three orifices belonging to the lai'ge milk ducts by 

 Avhich the milk is extracted from the gland. The integumentary 

 covering of both glands and teats is thinner than the surrounding skin, 

 and it is generally black-pigmented. Moreover, the ordinary body haii-s 

 are absent over it, their place being taken by a fine down, except over 

 the summit of the teat, where there are no hairs. It is richly provided 

 with sebaceous and sudoriparous glands, whose secretion renders it 

 moist. 



When the cutaneous covering of the gland is reflected, there is 

 exposed a second envelope, composed of yellow elastic tissue. This 

 covering detaches a number of processes into the interior of the gland 



