Thomson, J. A. (1922). The teaching of sex hygiene to boys. In Anonymous, The new educators library. Experimental psychology and child study (pp. 119-122). London, Great Britain: Sir Isaac Pitman & Sons.
http://dx.doi.org/10.1037/13550-019
This treatment on the teaching of sex hygiene to boys concludes with a quotation from the volume on Sex: "Whether the sex-instruction is direct or indirect, through hygiene or through nature study; whether it is given by the parent or by the head of the school, by the science teacher or by lending booklets--care must be taken not to anticipate interest; not to excite; not to say what is untrue; not to teach what will have to be unlearned afterwards; not to make false mysteries (such as dusting a stigma with a pollen laden feather might dispel); not to deal with the pathological; not to frighten; not to pretend that men and women are angels; and, above all, not to say too much." (PsycINFO Database Record (c) 2016 APA, all rights reserved)