This time has been gradually extended until the expectancy of life is now estimated at from 56 to 58 years, no less than nine of which have been added during the first quarter of the present century. The remarkable strides of the last 60 years have been largely due to the advancement in surgery, and to the more efficient control and prevention of communicable disease. It is in this latter field that the work with which we are concerned plays an essential part. Prominently associated with the achievements of the nineteenth century are the names of Lord Lister, Pasteur, Von Behring, and Koch. Certified Milk has set a standard for the production and handling of milk that has influenced the entire industry.
Pasteurization is the other great factor in improvement.
Within the last couple of years, commercial pasteurization has been submitted to a more searching scrutiny on the part of public health officials. In some cases, a wide gap was found between technical pasteurization and the commercial so-called pasteurization practiced. The net result of these investigations will undoubtedly be the more efficient application of this valuable safeguard. Coupled with this improvement in the general quality and wholesomeness of public milk supplies, there has been an increasing appreciation of the nutritive value of this important food, and the per capita consumption of milk and dairy products on this continent is daily increasing. In times past, owing to the distance from the source of supply, the perishable nature of the product, and the risk of contamination on transit, the great problem lay in supplying the larger cities with a safe milk supply.