It is obvious that if `desirability', in the above definition, were interpreted hedonistically, the term ``health'' would merely give us a new name for the general problem of utilitarian morality; not a new suggestion for its solution. I ought to say that the notions of ``social welfare'' or ``wellbeing'' are elsewhere used by Mr. Stephen, in the place of those here quoted, but I do not think that he means by them any more than what I understand him to mean by ``health'' or ``efficiency''---i.e. that state of the social organism which tends to its preservation under the conditions of its existence.