The skin which lines the internal surface of the external lips is folded in such manner as to form two flat bodies, the exterior edges of which are convex. They are called the nymphse. They extend downward, one on each side, from the clitoris to near the middle of the external orifice, somewhat diverging from each other. Their use is not very evident The orifice of the urethra (the canal, short in females, which leads to the bladder) is situated an inch or more farther inward than the clitoris, and is a little protuberant. Passing by the external lips, the clitoris, the nymphse and the orifice of the urethra, we come to the membrane called the hymen. It is situated just at, or a trifle behind the orifice of the urethra. It is stretched across the passage, and were it a complete septum, it would close up the anterior extremity of that portion of the passage which is called the vagina. But the instances in which the septum or partition is complete are very rare, there being, in almost all cases, an aperture either in its center, or frequently in its anterior edge, giving the membrane the form of a crescent Through this aperture passes the menstrual fluid. Sometimes, however, this septum is complete, and the menstrual fluid is retained month after month, until appearances and symptoms much like those of pregnancy are produced, giving rise to perhaps unjust suspicions. Such cases require the simple operation of dividing the hymen. In many instances the hymen is very imperfect, insomuch that some have doubted whether it is to be found in the generality of virgins. Where it exists it is generally ruptured in the first intercourse of the sexes, and the female is said to lose her virginity. In some rare instances it is so very strong as not to be ruptured by such intercourse, and the nature of the difficulty not being understood, the husband has sued for a divorce. But everything may be put to rights by a slight surgical operation. The parts here described are among those called the external parts of generation. The internal organs of generation consist in the female of the Vagina, the Uterus, the Ovaries and their appendages. The Vagina is a membranous canal commencing at the hymen and extending to the uterus. It is a little curved, and extends backward and upward between the bladder, which lies before and above it, and that extreme portion of the bowels called the rectum, which lies behind it. The coat of membrane which lines the internal surface of the vagina forms a number of transverse ridges. These are to be found only in the lower or anterior half of the vagina, and they do not extend all round the vagina, but are situated on its anterior and posterior sides, while their lateral sides are smooth. I mention these ridges because a knowledge of them may lead to a more effectual use of one of the checks to be made known hereafter.