420 PHYSIOLOGY. 



Ott and Scott have found 2 i hours alter the extirpation of the 

 superior cervical ganglion that the local, venous or subcutaneous use 

 of pituitary dilated the pupil, but not affecting the pupil on the sound 

 side. In this respect it resembles the action of adrenalin on the 

 mammalian pupil. The frog's pupil is dilated by adrenalin and 

 pituitary. 



Ablation of this body in the cat produces death in about two 

 weeks. The symptoms resemble very much those that follow thy- 

 roidectomy. Extracts of the infundibular part elevate the arterial 

 tension by a constriction of the arteries and slow the heart. This 

 substance is not soluble in alcohol. From a saline decoction of the 

 gland there was obtained an alcoholic precipitate which produced a 

 fall of arterial tension; so that there seem to be two substances in 

 this gland, antagonizing each other as regards arterial tension. 

 Pituitary dilates renal arteries. Disease of this gland produces the 

 condition known as acromegaly, in which the bones of the face and 

 limbs become hypertrophied. It is also connected with giantism. 



EXTERNAL SECRETIONS. 

 THE MAMMARY GLANDS. 



The mammae, or breasts, are accessory organs of the generative 

 system. They secrete the milk. They exist in the male as well as in 

 the female, but only in a rudimentary condition in the former. In 

 the female they are two large, hemispherical eminences situated 

 toward the lateral aspect of the pectoral region. They range between 

 the third and seventh ribs. Before puberty they are of small size, but 

 enlarge as the generative organs become more fully developed. They 

 enlarge during pregnancy, especially after delivery. In old age they 

 become atrophied. 



The outer surface of the mammas is convex, with just below the 

 center a small, conical eminence: the nipple. The surfa.ce of the 

 nipple is dark-colored, and surrounded by an areola of a colored tint. 

 In the virgin the areola is of a delicate, rosy hue; about the second 

 month after impregnation it enlarges and also acquires a darker 

 shade of color. The color deepens as pregnancy advances; in some 

 cases it becomes dark brown or even black. After cessation of lacta- 

 tion there is a diminution in the quantity of pigment, but the 

 original hue is never regained. Change in the color of the areola is 

 of importance in determining an. opinion in /jases of suspected first 

 pregnancy. 



