Two general terms, "sex-instruction" and "sex-education," are available as all-inclusive designations of the desirable instruction concerning any aspects of sex. They are quite free from the above objections to "sex-hygiene," and it is highly desirable that they should be used in all educational discussions where there is no specific reference to the problems of health. Sex-hygiene will be used in these lectures only when there is some direct reference to health as influenced by the sexual functions. [Sidenote: Social hygiene.] Social hygiene in its complete sense means the great general movement for the improvement of the conditions of life in all lines in which there is social ill health or need of social reform; but it is often limited to the sexual aspect of the unfortunate and unfavorable conditions of life, and it has been proposed to adopt the term "social hygiene" as a substitute that avoids the word "sex" in sex-hygiene. For this reason it has been incorporated into the names of several societies that are interested in sex-hygiene (_e.g._, the American Social Hygiene Association). Probably the relation of sex-hygiene to the so-called "social evil" has suggested the use of social hygiene in its most limited sense. It will be unfortunate if this usage becomes so prominent that we think of the health problems of society as chiefly sexual, for the larger outlook of Ellis's "Task of Social Hygiene" is desirable. Likewise, the phrase "social evil" in the sense of sexual evil misleadingly suggests that the only evil of society is the sexual one, but this evasive designation is being supplanted by the more definite and franker word "prostitution." It should be noted that "social hygiene" as a substitute for "sex-hygiene" is narrower in that it does not include the personal problems of health as affected by sexual processes. This is a serious omission, for certainly all sex-hygiene taught before the later adolescent years should be personal and not social. [Sidenote: Phases of sex-education.] The relation of sex-hygiene or social hygiene as a limited phase of sex-education is shown by the following outline: