THE SKTX AXD ITS APPENDAGES 407 



Development. — The development of ihe mammary gland is quite similar 

 to the development of the sebaceous glands. The gland first appears as a 

 dipping down of solid cord-like masses of cells from the stratum mucosum. 

 The alveoli remain rudimentary until the advent of pregnane}'. After lacta- 

 tion the alveoli atrophy, being replaced by connective tissue, and the gland 

 returns to the resting state. After the menopause a permanent atrophy of 

 the gland begins, fat and connective tissue ultimately almost wholly replacing 

 the glandular elements. 



TECHNIC 



(i) Fix thin slices of an inactive mammary gland in formalin-Miiller's fluid 

 (technic 6, p. 7). Stain sections with haimatoxylin-cosin (technic i, p. 20), and 

 mount in balsam. 



(2) Prepare sections of an active mammary gland, as in preceding technic (i). 



(3) Fix very thin small pieces of an active gland in one per cent, aqueous 

 solution of osmic acid. After twenty-four hours wash in water and harden in 

 graded alcohols. Thin sections may be mounted unstained, or after slight eosin 

 stain, in glycerin. 



General References for Further Study 



Kolliker; Handbuch der Gewebelehre des Menschen. 

 ]\Ic;Murrick: Development of the Human body. 

 Ranvier: Traite Technique d' Histologic. 

 Schafer: Essentials of Histology. 



Spalteholz: Die Vertheilung der Blutgefasse in der Haut. Arch. Anat. u. 

 Phys., Anat. Abth., 1893. 



