Guyot, Bréviaire de l'Amour Expérimental, p. 144.
Erb, Ziemssen's Handbuch, Bd. xi, ii, p. 148. Guttceit also considered that the very wide variations found are congenital and natural. It may be added that some believe that there are racial variations. Thus it has been stated that the genital force of the Englishman is low, and that of the Frenchman (especially Provençal, Languedocian, and Gascon) high, while Löwenfeld believes that the Germanic race excels the French in aptitude to repeat the sex act frequently. It is probable that little weight attaches to these opinions, and that the chief differences are individual rather than racial.
Ribbing, L'Hygiène Sexualle, p. 75. Kisch, in his Sexual Life of Woman, expresses the same opinion.