Anatomy and Physiology of the Mammary Glayid. 8$) 



corresponding- quantity of blood for its secretion. We find, 

 therefore, that the arteries going to the udder are both large and 

 numerous ; and tliat the branches of each vessel freely anastomose 

 together, so that no interruption to the regularity of the supply of 

 blood to every part of the gland may take place. The anterior por- 

 tions of the mammae receive their blood chiefly from the internal 

 pectoral arteries, which quitting the chest run in a backward course 

 to reach the glands. The posterior parts are supplied principally 

 by branches, called the mammary arteries, which come off from the 

 epigastric artery. In addition to these the circumjlex artery oj the 

 ileum sends numerous branches to the glands, which likewise 

 freely anastomose with the other vessels. The several vessels 

 which come off from these trunks penetrate into the substance of 

 the mammae, within which they freely ramify by numerous divi- 

 sions and subdivisions. Ultimately, by further splittings up and 

 consequent diminution of their calibre, they form vessels so minute 

 as to be unobservable to the naked eye, and which have been 

 designated capillaries. These are distributed to the follicles or 

 ccecal extremities of the lactiferous ducts, upon which .they form 

 a minute rete of vessels, and furnish blood both in sufficient 

 quantity and also in a condition fitted for the secretion of milk. 

 The annexed woodcut, Fig. 4, represents the ccecal exiremiiies 



Fig. 4. 



A highly-magnified view of the coecal 

 extremities or follicles of the lactiferous 

 ducts, in which tlie secretion of milk 

 takes place. The Hark lines, which 

 form a net-like structure on these vesi- 

 cular bodies, represent the capillary 

 vessels by « hich the blood is distributed 

 for the secretion. 



of the lactiferous ducts, highly magnified, and surrounded by their 

 net-like structure of capillaries. From the ccecal extremities the 

 milk, as quitkly as it is formed, finds its way along the minute 

 excretory ducts to which they are attached, into larger tubes, and 

 thence into various-sized cavities which are termed reservoirs. 

 The arrangement of this portion of the gland may be compared 

 to bunches of currants as connected with or growing upon their 

 foot-stalks. The fruit would here represent the milk-secreting 

 follicles, and the stalks the tubes by which it was conveyed 



