92 Anatomy and Physiolofjy of the Mammary Gland. 



We come now to speak of the veins of the mammae, which 

 are likewise shown in Fig. 6, d, d, and e, e. These are verj 

 numerous and large, it being necessary that every facility should 

 be given for the return into the system of the blood which has 

 not been appropriated for the secretion of milk or for the main- 

 tenance of the integrity of the glands. Taking their rise chiefly 

 from the capillarv network of the milk follicles, the small venules 

 coalesce to form distinct branches of veins — the mammary veins. 

 Many of these pursue a course towards the upper and back part 

 of the udder, while others proceed towards the upper and front 

 part of it, for the purpose of carrying the blood into large vessels 

 which are met with in both these situations. The veins which 

 pass backwards empty themselves into the inguinal, and these 

 in turn into the iliac veins, by which this portion of the bh)od is 

 returned to the heart through the posterior vena cava. Those on 

 the contrary which proceed forward convey the blood into large 

 vessels — the superficial abdominal veins — commonly known as 

 the milk veins, and by them it is transmitted into the internal 

 pectoral veins, reaching the heart by means of the anterior vena 

 cava. The size of the superficial abdominal vein (see e. Fig. 6) 

 on either side of the belly, sufficiently indicates that the greater 

 part of the blood coming from the udder passes through them. 

 Notwithstanding, however, the position which these vessels hold 

 with regard to the mammae, and the common opinion which 

 assigns a Vcilue to them as an indicationof the milking properties 

 of the cow, Mr. Youatt, in his work on Cattle, describes them as 

 belonging principally to the chest, or, as he says, " to the respira- 

 tory system more than to any other." * Quoting from Giiard's 

 Anatomy, he gives an elaborate account of the origin, course, and 

 distribution of the superficial abdominal vein, and absolutely by 

 this reverses the course of the current of blood within it, describ- 

 ing the fluid as flowing in the opposite direction from that which it 

 really does. Further on he censures the veterinary surgeon who 

 should open this vein in treating diseases of the mammae, by 

 remarking that " if we were to have recourse to bleeding from 

 this vein in garget, or any inflammatory affection of the udder, 

 we should betray our ignorance of anatomy." It is very re- 

 markable that such an error as this should have crept into the writ- 

 ings of one so deservedly estimated as an authority on veterinary 

 science, and our only object in alluding to it is to set the agricul- 

 turist right with regard to the true office of the superficial abdo- 

 minal veins, and the propriety of taking blood from them in cases 

 of inflammation of the mammary glands. 



To this description of the arteries and veins of the udder, we 



* Cattle, page 349. 



