The American journal of anatomy . 358 STUDIES ON THE MAMMARY GLAND 359 A very good time to make these observations on the albinorat is about the tenth to the fourteenth day of Ufe. As pointedout by Jackson (12), the mammary glands (nipples) are veryconspicuous at this time. After the first two weeks have passed,it is very difficult to make accurate observations as the glandsare well covered with dense hair. During pregnancy and theperiod of lactation the glands again become very conspicuous. Just medial to the apex of each nipple is a single opening whichleads into one large
The American journal of anatomy . 358 STUDIES ON THE MAMMARY GLAND 359 A very good time to make these observations on the albinorat is about the tenth to the fourteenth day of Ufe. As pointedout by Jackson (12), the mammary glands (nipples) are veryconspicuous at this time. After the first two weeks have passed,it is very difficult to make accurate observations as the glandsare well covered with dense hair. During pregnancy and theperiod of lactation the glands again become very conspicuous. Just medial to the apex of each nipple is a single opening whichleads into one large duct. This duct after reaching the tela sub-cutanea turns almost at right angles and courses through thislayer parallel to the surface. Instead of receiving a large numberof tributaries from all directions, this single duct at first receivesonly a small number of tributaries usually from a single direc-tion. Figure 2, drawn from a cleared preparation of the integu-ment of a rat two weeks old, will serve to show the general direc-tion taken by the
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Keywords: ., bookauthorwi, bookcentury1900, bookdecade1910, booksubjectanatomy
