Miss X. is 26 years of age. Her father she describes as a healthy but very irritable man. Already at the age of 5 she had carried on certain sexual plays _with a small boy_. She admits having attempted intercourse at the time with the boy who was four years of age. The intercourse consisted of _mutual cunnilingus_. At six years of age she was sent to school and here she soon began intimate relations with small girls. With a number of them she carried on mutual _cunnilingus_ as she had done with the boy. From the time when she first began this with the girls her heterosexual inclination disappeared completely; after that she never again went through a similar experience with a boy. We shall see that later she did allow herself to be used occasionally by men; but we must note in that connection that the heterosexual acts took place without the cooperation of sexual feelings on her part. At 12 years of age she began to menstruate. At that time she had as playmates the children of a neighborly family who had a governess with whom she soon entered into close intimacy. The governess prevailed upon her to carry on sexual acts, particularly _cunnilingus_, and the active part was taken now by each in turn from time to time. In the course of these relations she experienced for the first time sexual gratification, so far as she is able to recall. Their intimacy lasted for some time. Miss X. differs from other women of her type in that she is not averse to other forms of gratification. Soon she sought also _anus feminarum amatarum lambere_, in addition to the genitals. The thought of carrying out such an act with a man was repulsive to her. Just as we know that occasionally perverse men want _urinam feminæ dilectæ in os proprium immittere_ so we see that Miss X. likes to have the same thing done to her by other girls. For a number of years already Miss X. has been in the habit of allowing _fæces amicæ in os proprium iniciire_; the act produces in her gratification and orgasm. She had first indulged in these acts during her intercourse with the governess above mentioned, which lasted several years. Miss X. is also tremendously roused when she _sanguinem menstruationis amicæ lambit et devorat_; but, she explains that she is able to carry out these disgusting acts only when there is complete mutual confidence and only if the relationship has endured for some time. She declares further that she is sexually roused also when she is struck with a whip. When asked how she came to acquire this habit she answered that she knew a man who required to be thus treated by a former sweetheart. But, to secure her any sexual excitement the whiplashes must fall upon her from the hands of a woman. She has allowed herself very often to be flagellated by her friend with whom she has also been carrying on the disgusting acts mentioned above. It may be mentioned also that when they kiss each other Miss X. wants to be bitten by her friend, preferably upon the ear lobe.