So vital and rapidly growing are these bacteria that they would soon, under favorable conditions, outbulk the entire body. But while their numbers are kept down by lack of nutriment and other conditions, nature provides no adequate antidote to their activity. This was found by Woolman and was called glycobacterium, or the sugar-maker. It was found first in the dog, and it can be cultivated in the laboratory and introduced into the body. It transforms starch into sugar without affecting the albuminoids and it is not, like sugar, absorbed before it reaches the large intestine. Thus it is not sugar that is the antidote but the lactic acid of its product and this is found in nature in the bacillus of sour milk, a common article of diet among Bulgarians, who seem to be the longest-lived people in Europe. The results of experiments with this product, first upon rats and other animals, Metchnikoff thought remarkably rejuvenating; and as all know, many substances containing lactic acid were for a long time in great favor, although expectations of its effectiveness have by no means been fulfilled. The death of Metchnikoff himself, too, at the age of seventy-one, who had long and diligently used his own panacea, did not help the confidence of his disciples, for we can never forget the old slogan, “Physician, heal thyself.” In Sanger’s returns to his questionnaire,[170] as well as to my own, one often finds people who use some form of this preparation and with what they deem good results and Metchnikoff’s volumes show such a unique combination of humanistic and scientific interests that they have had wide popularity.