Impotence of voluptas is also often found in dementia. Sometimes impotence of voluptas is congenital with an individual otherwise normal. The impotence is then analogous to colorblindness. Such cases are exceedingly rare. _Impotence of libido._—Similar to impotence of voluptas is the impotence of libido. Here the desire is powerful, the erections are vigorous, yet ejaculation takes place without the usual accompanied libido. It is analogous to the loss or impairment of the sense of taste. Idiopathic impotence of libido in men is very rare. It is mostly found as a symptom of some other anomaly. Impotence of libido exists in cases of loss of testicles, as in castrates and eunuchs. As a rule, impotence of libido is met with in men who have severely over-taxed their brains and hence are less impressionable than when in a normal state of health. The impotency is an indication of an exhausted brain where the centres for experiencing libido reside. Sometimes the centripetal nerves which serve for transmission of the pleasurable sensations to the centres have their impressionability obtunded by excesses in venere. When the nerves are deranged, the desire is strong, the erectile power is sufficient, the mind is in concurrence, emission occurs at the right moment, yet scarcely a vestige of pleasurable sensation is experienced during emission. The following case may serve as a proper illustration of the nature of this anomaly. Mr. X., fifty years of age, was seduced to the practice of manusturpation when about thirteen years old. The exercises were carried out daily. After puberty, from about sixteen to nineteen years of age, he was given less to these practices, still once a week he could not resist of indulging in his favorite pastime. At this time he began to associate with meretricious women. This activity alternated with manusturpation until he was forty years old. There were periods of months or even years, while living in localities where the opportunity for normal sex activity was entirely lacking, when he took refuge to weekly practices of manusturpation. At the same time he indulged in excesses of mental erethism. His day-dreams on his long walks and in sleepless nights were filled with images, all taken from the realm of sex. Sometimes he also indulged in excesses of tactile eroticism (manibus ludere cum genitalibus mulierum). At the age of forty he married a very attractive young woman, and although he is greatly in love with his wife and two children, who arrived in the course of time, and is leading a regular sex-life, still the pleasure experienced at the ejaculation is practically nil. What induces him to still keep up his sexual activity is to please his young wife.