ing for whatever is positively useful. In other words, two principles are recognized as determining the character of animal forms: 1. Natural selection, which implies the production of such structures as are useful in the particular environments m which the animal is placed. 2. The influence of the structure already acquired at any given period of development—this being determined by heredity. But heredity itself represents the organized product of a permanent environment, as illustrated, for example, in the hereditary blindness of fishes living in Mammoth Cave; or, better still, in the respiratory mechanism of all water-breathing animals; so that the environment is the ultimate factor which determines the specific character of animal forms—the structure developing slowly in accordance with this influence.
Similarly in the department of morals, two factors must be recognized as determining conduct: 1. Those qualities of character belonging by inheritance to the organized structure of body and brain. 2. Those influences which grow out of the social environment, which are constantly modifying the inherited nature, and building up a corresponding character. In my proposition, then, to found a city in which any given degree of morality, within certain limits, may be secured, these limits are understood to depend on the laws of inherited character; while the modifiable morality (that which may or may not be secured at the option of the founder of the city) is that which depends on the particular environment, physical and social, determined upon by the founder; the inherited character, also, like the inherited bodily organism, being subject to modification from this source. To discuss this proposition in a manner commensurate with its importance, would take us too far afield for the present occasion, since it would involve a consideration of the whole subject of the origin and evolution of morals. Your attention is, therefore, invited to a few only, and those the more obvious, points connected with this proposition of securing a given morality-rate within certain limits, inherently as definable, although not as precisely defined, as in the case of the proposition with reference to the mortality-rate.
As a result of Mr. Chadwick's statement, Dr. B. W. Richardson (in the address referred to) projected a city of health, which he named Hygeia (and which it is scarcely necessary to premise was located in Spain!) in which all the modern sanitary inventions and precautions calculated either to promote health or to prevent disease, were grouped together in a picture most delightful to the mind's eye of every sanitarian. This model city, Hygeia, with some alterations and additions, would furnish the material substratum of the possible city of which I have spoken, and which I would name Ethica. A brief glance at the general features of our model will serve to bring the subject fairly before us.
First, and most conspicuously, we note that overcrowding in this city of health is impossible—made so by the style and location of the
