several generations, precisely the opposite of that course which makes a bad constitution out of a good one. Any one who has attained to life's meridian will be able to recall examples of good constitutions converted into bad ones. Children, parents, and grandparents, in some families, often stand thus in regard to constitutions:
Grandparents scarcely know what sickness is, and die of old age;
Parents: constitutions much impaired, often sick, and die in middle life;
Children: constitutions very defective, and are rarely well a week at a time.
This is the downward career of life-force, which almost every one has witnessed; the upward career being the result of a precisely opposite course. In place of abusing the constitution there is the most careful husbanding of its resources, and avoidance of all the causes which will impair its vigor. The purity and strength which such a course of conduct begets is transmitted; the child starts in the world on a higher plane of life-force than the parents did; and if the offspring continue to carry out the reformation thus inaugurated, the result will be to bring back the pristine vigor, health, and longevity, which an opposite course had destroyed.
Such are some of the elementary truths forced upon the attention by everyday experience on the great problem of obliterating sickness and death by disease. As has been stated, these elements of sanitary science have long been known. But in spite of this, and of the facts that this science has of late been purged of many errors, and its bearings and capabilities greatly extended, disease, deformity, decrepitude, and untimely death, prevail almost as much as ever. Where, then, is the weak point in sanitary science? Is it in the imperfection of the science itself, or is it in its applications? Reverting to the history of electrical discovery and its applications, will give us aid in solving the question. We have seen that the discovery of the great truths about the electrical force employed one class of scientific experts, and applying these truths employed another class of scientific experts. Now, we have had in abundance the discoverers of the truths of sanitary law, but we have not, nor can we have, as in electricity, experts who can carry out for the advantage of all, the benefits which hygienic law is capable of conferring. There cannot be, in sanitary matters, ingenious contrivances, by which a certain class of men can manipulate health and long life into their fellow-beings. Its truths, if applied at all, must be mainly applied by those who desire its benefits; or every one must apply the science for himself or herself, else nearly all the knowledge there may be on the subject will be as if it were not. Here we have plainly before the mind the great and peculiarly weak point, so far as the practical benefits are concerned, which this science may be capable of conferring. To make it profitable and useful, or, in other words, to make it an applied science in a community, that
