290 THE ADRENAL SYSTEM AND VASOMOTOR FUNCTIONS. 



such a deduction could be based, in respect to the latter organ, 

 could be accounted for without vasodilators and that active 

 dilation was a mechanical impossibility. Claude Bernard's own 

 testimony to this is indirectly afforded by the fact that the 

 "interference" or "inhibition" theory was introduced by him 

 to account for vasodilation: the existence of which he was 

 first as he had been in the case of vasoconstriction to dem- 

 onstrate. 



The various data reviewed seem to us, when considered col- 

 lectively, to suggest modifications of generally accepted views. 

 In the mammary gland the secreting apparatus is formed, we 

 have seen, first, by an extremely thin basement membrane, and, 

 second, by a single layer of epithelial secretory cells. The 

 latter supply the milk-forming elements other than the liquid 

 per se, which liquid responds to various tests of blood-plasma 

 (Duval) and seems to replace the water secreted by the sweat, 

 salivary, and lacrymal glands. In all three of the latter organs, 

 however, the secreting structures are surrounded by a net-work 

 of capillaries. That such is also the case in the mammary 

 gland is evident, since Piersol, 15 referring to the glandular 

 vessels, says: "From these vessels on the anterior surface of 

 the organ branches penetrate into the glandular mass and 

 pass between the lobules, giving off twigs which break up into 

 capillaries inclosing the alveoli. 7 ' A net-work of nerve-fila- 

 ments are also traced to the glandular elements of salivary 

 and sudoriferous glands: a feature also reproduced in the 

 mammse. Thus, Bohm and von Davidoff, 16 alluding to the 

 terminations of the nerves in the mammary glands, recall that 

 they have been studied by means of the methylene-blue method 

 by Dmitrewsky, who found that "the terminal branches form 

 epilamellar plexuses outside the basement membrane of the 

 alveoli, from which fine nerve-branches pass through the base- 

 ment membrane and end on the gland-cells in clusters of 

 terminal granules united by fine filaments." They also state 

 that "the vessels form capillary net-works surrounding the 

 alveoli." The ducts when nearing the nipple have an outer 



15 Piersol: "Normal Histology," p. 241, seventh edition, 1900. 

 18 Bohm and von Davidoff: "Text-book of Histology," translated by Huber, 

 p. 361, 1900. 



