P. Janet, "La Maladie du Scrupule," Revue Philosophique, May, 1901.
S. Freud, Sexual-Probleme, March, 1908. As Adele Schreiber also points out (Mutterschutz, Jan., 1907, p. 30), it is not enough to prove that abstinence is not dangerous; we have to remember that the spiritual and physical energy used up in repressing this mighty instinct often reduces a joyous and energetic nature to a weary and faded shadow. Similarly, Helene Stöcker (Die Liebe und die Frauen, p. 105) says: "The question whether abstinence is harmful is, to say the truth, a ridiculous question. One needs to be no nervous specialist to know, as a matter of course, that a life of happy love and marriage is the healthy life, and its complete absence cannot fail to lead to severe psychic depression, even if no direct physiological disturbances can be demonstrated."
Max Flesch, "Ehe, Hygine und Sexuelle Moral," Mutterschutz, 1905, Heft 7.