The generative centres are particularly damaged by the constant congestion of the genitals. The frequent stimuli keep the lumbar centres in a condition of constant irritation. The nervous system, presiding over the function of erection, thus becomes worn out and exhausted, and the nerves do not respond even to the strongest stimulations, which would otherwise set them in action. In this way, the centres get accustomed, so to say, of not responding any longer with erection to the proper stimuli, or in other words, the consensualism between the genital nerves and their centres is broken. Hence, besides the harm done to the nerves by the general debility, there is great damage done to the genital nerves and centres by the break in the chain of the reflex mechanism. In no other sex-activity, except in actual copulation, are the generative organs in such a constant and intense excitement as in dalliance with individuals of the other sex, no other erotic stimuli create such libidinous turgescence of the organs and such a high degree of sex-tension, exciting with rapture the higher centres, no other excitations cause such a consumption of nerve power as this gratification of the impulse of contrectation by tactile manoevres. The erections of penis and clitoris are vigorous and violent. The organs are set in a state of expectancy for the final act. If the act is not terminated within a certain limited time, the state of expectancy cannot last for ever. The mode of action is limited in length of time. Except in the abnormal state, known as priapism, the duration of erection is relatively short in the normal individual. Its beginning is synchronous with the onset of the material congestion and nervous tension of the genital parts, and its subsidence should normally be synchronous with ejaculation. If the latter be prevented, erection has to cease sooner or later, even when congestion and tension remain unabated. Hence after long and lasting amorous caresses the erections fail. If these manœuvres are often repeated, the excitations finally do not effect the proper response, and erection fails from the outset. The strong and continuous stimulations render the nerves and their centres inert in reaction and weak in power. The centres of erection and ejaculation become blunted, the inhibitory centres get very sensitive, and erection cannot be provoked. When the nerve centres presiding over the function of erection get into the habit of not responding to the highest excitations of the tactile stimuli, they do not respond even to the stimulations concarnationis. The cooperating nerve-apparatus has been affected, and a perverted innervation is created. The close interdependence of the mechanism of erection and the centres is removed, and an abnormal reflex-excitability is produced. The consensualism between the corpora cavernosa and the centre of erection is interrupted.