262 



NORMAL HISTOLOGY. 



squamous epithelium for a short distance from the vestibule, the remainder 

 of the passage and its subdivisions being clothed with columnar cells. 



The glands of Bartholin, the largest of the vestibular and the homo- 

 logues of the bulbo-urethral (Cowper's) glands, are two small organs, 11.5 

 cm. in length, situated one on either side of the vaginal orifice. They are 

 tubo-alveolar mucous in type and produce a whitish viscid secretion. The 

 small component lobules are separated by considerable tracts of fibro- 

 muscular tissue and lined with columnar epithelium containing many mucus- 

 bearing cells. The lobular ducts unite to form the single excretory canal, 

 which is beset with minute mucous follicles. The main duct, sometimes 

 provided with an ampullary dilatation, is lined with columnar epithelium 

 until near its termination, where the epithelium becomes stratified squamous 

 to correspond with that of the vestibule. 



The clitoris, the homologue of the penis, possesses in reduced and 

 modified form the chief components of the male organ. It consists essen- 

 tially of two miniature corpora cavernosa and an imperfectly developed and 

 cleft corpus spongiosum, known as the bulbus vestibuli. The latter consists 

 of two converging elongated masses of cavernous tissue a complex of 

 tortuous veins and fibro-muscular tissue. The glans and carvernous bodies 

 repeat, although in less typical manner, the histological details described in 

 connection with the corresponding parts of the male (page 239). 



Excretory duct 



THE MAMMARY GLANDS. 



Although morphologically modified cutaneous glands and developed in 

 both sexes, the functional importance of the mammary glands, or mamma, 

 in the female entitles them to be regarded as organs accessory to the 



reproductive apparatus. 

 Each mamma, or 

 breast, comprises a 

 group of some twenty 

 individual and separate 

 glands, opening on the 

 nipple by independent 

 ducts, that collectively 

 constitute the secreting 

 organ, the corpus mam- 

 ma, as distinguished 

 from the enveloping fat 

 and areolar tissue. Prior 

 to the changes incident 

 to pregnancy, the secre- 

 tory tissue is relatively 

 meagre and overshad- 

 owed by the fat-laden 

 connective tissue in 

 which the still rudi- 

 mentary alveoli are em- 



Involuntary 

 muscle 



FIG. 310. Section of mammary gland before lactation. X 170. 



The corpus mam- 



mae consists of from 15-20 or more flattened pyramidal lobes, radially 

 disposed, with the bases directed towards the periphery and the excretory 

 canals, the lactiferous ducts, converging towards the nipple upon which they 



