288 THE ADRENAL SYSTEM AND VASOMOTOR FUNCTIONS. 



stage. Its contained cells are much more numerous than at 

 any other period, and they form a perfect mosaic, lining the 

 membrana propria. Each cell is flattened and of polyhedric 

 shape, and has a large nucleus surrounded by a broad zone of 

 protoplasm. 



"During the period of subsiding function the organ grad- 

 ually reverts to the resting stage through the converse series 

 of changes. In this process the cells pass through a succession 

 of transformations, from the forms characteristic of the per- 

 fect mosaic of lactation to those peculiar to the various stages 

 of the subsiding process. These changes are accompanied by 

 constant destruction and renewal of the participating cells. 



"With regard to the influence of the nervous system on 



FIG. 4. EXPANDED MAMMARY ACINUS, SHOWING THE ARRANGEMENT 

 OF EPITHELIAL MOSAIC. (Creighton.) 



the mammary secretion, most of those who have studied the 

 subject are agreed that the secretion of milk is not directly 

 under its control. Laffont, 13 however, maintains that the 

 mammaB possess vasodilator nerves which, when stimulated, 

 cause augmentation of the quantity of milk secreted; but de 

 Sinety, 14 who has repeated his experiments, is unable to accept 

 his conclusions." 



The foregoing review not only indicates the important 

 part cellular metabolism plays in the functions of the mam- 

 mary glands, but also that the blood is an important source 

 of active functional work. "The blood is the ultimate source 



18 Laffont: Comptes-Rendus de l'Acadmie des Sciences, vol. Ixxxix, 1879. 

 De Sinety: Memoires de la Societe de Biologie, vol. i, 1879. 



