"The Bacillus of Long Life" is certainly a pretentious and attractive title for a book. Its basis is, of course, the dream of Metchnikoff, that the persistent consumption of sour or fermented milk destroys poison-producing bacteria in the intestinal tract of man and replaces them by long-life-bringing bacteria. Unfortunately, the investigations which are supposed to bear out this theory are not above criticism, although the author takes the stand that they are indisputable. After considering the results of these investigations, coupled with statements from Metchnikoff's book "The Prolongation of Life." the author thinks it but a short step to conclude that the Bacillus bulgaricus may claim to be the bacillus of long life.
There are several interesting and meritorious chapters in the book. The accounts and historical data of fermented milks used by different races are of considerable value. Following these, the chemistry of milk is popularly discussed. It is