tific knowledge that teaches how life is to be protected and prolonged, disease prevented, health heightened, and human existence made more valuable. While at Cambridge they have been assiduous in conserving the more worthless kinds of knowledge and preventing thoroughness in any, in London men have been voluntarily combining to secure the more thorough application of scientific methods to household sanitation. Great multitudes die from unhealthy habitations. Their dwellings are poisoned by noxious emanations that give rise both to slow undermining maladies and to swift malignant diseases. Prominent among these destructive contaminations is sewer-gas, and science has at length grappled with the problem of getting effectually rid of it. It was at first supposed to be an easy task. "Traps" were interposed to prevent the refluence of sewage exhalations, and all was supposed to be well. But disease and death were still rife, and further investigation showed the inefficacy of the mechanical arrangements, and. that "foul gases will pass steadily, continuously, and certainly through water in traps." Yet it can not be for a moment doubted that it is possible to obtain absolute protection in dwellings against sewer-air. The difficulty is to get the ignorant classes (including the educated) to give that serious attention to the subject which its gravity demands. The work must be done by the comparatively few who have mastered the science of the question.
Much has been accomplished by such men in this country as well as abroad. But we observe that they are organizing in London for the most effectual prosecution of this important work. A Sanitary Assurance Association has been formed under the presidency of an eminent physician, Sir Joseph Fayrer, the design of which is to unite the professions of medicine and architecture to secure the thorough supervision of sanitary arrangements and drainage in the houses of the metropolis. It seems not to be a movement of evasion by getting up a cry for more "government inspection," but a voluntary association of qualified men who are ready to meet the responsibilities of the task they undertake. Assuming that defective drainage is a "great enemy to public health," and that "there is a terrible absence of all supervision of sanitary arrangements," the Sanitary Assurance Association will make a careful investigation of the health-conditions of houses, and give certificates to those that are in perfect sanitary order. This will be of most important service to the public, because people generally are incompetent to determine what houses are healthy and what are unhealthy. The names of the men who are foremost in this movement are a guarantee that it will be well directed, and, if it achieves the success that it promises, kindred associations will spring up in many other places. A writer, giving a notice of this organization in "Nature," remarks: "It is surely as necessary to be assured against preventable diseases as it is to be assured against fire, and we see from the preliminary prospectus issued that it is intended to give persons who place their houses on the Assurance Register certificates that their houses are in a satisfactory sanitary condition, and to endorse such certificates from time to time; this latter point is of great importance, as it is only by regular inspection at stated intervals that it is possible to ascertain that all continues to work satisfactorily."
We have been much gratified in looking over a modest pamphlet of sixty-two pages that has been sent to us, bearing the title of "Transactions No. 1 of the Ottawa Field-Naturalists' Club." Several young men of that Canadian city, interested in the subject, discussed