Effects of Extracts of Posterior Lobe of Pituitary 93 



to the breast, although there may be no actual outpouring of the 

 secretion. 



If in the experiment upon the cat the animal is killed immediately after 

 one of its glands (with nipple incised) has been emptied by an intravenous 

 injection of extract of posterior lobe in the manner above described, and if 

 a portion of tissue comprising parts of two adjacent mammae one emptied 



d 



FIG. 64. Effect on blood-pressure and mammary gland of a lactating cat of injecting extract 

 of 0'125 g. of posterior lobe of pituitary. (From K. Mackenzie, Quart. Journ. Exper. P/iysioL, 

 1911, vol. iv.) 



a, tracing of blood-pressure : notice that the main rise is preceded by a preliminary fall ; b, drops of milk 

 exuding from a fine canula introduced into one of the lactiferous ducts ; c, drops of milk exuding from 

 incised gland ; d, signal ; e, time in ten seconds. 



of its secretion as the result of the injection, the other with its alveoli still 

 full of milk is fixed and sections are made passing through both full and 

 empty mammae, the contrast in appearance is remarkable (fig. 65). In the 

 one, where the alveoli are distended with secretion, they are large and 

 rounded and the lining cells are flattened against the limiting membrane, 

 whilst in the other, from which the secretion has been discharged, the alveoli 

 are irregular, shrunk, and empty, their walls are folded, and the lining cells 

 stand prominently out from the limiting membrane. 



