The fact that so many races make soured milk and use it copiously is an excellent testimony to its usefulness. M. Nogueira has written to me to say how much he was astonished, on revisiting after a long period of absence the district of Mossamedes, to find the natives so well preserved and displaying so few traces of senility. Dr. Lima has stated that amongst the natives of the region south of Angola “many individuals of extraordinary longevity are to be found.” Although they are thin and withered, these old people are very active and can make long journeys. Mr. Wales, a lawyer at Binghampton, U.S.A., has been so good as to make me acquainted with some extremely interesting facts taken from a work by James Riley which is now a bibliographical rarity.[140] In the narrative of a shipwreck of the vessel on which he made a voyage in 1815, James Riley states that the wandering Arabs of the desert live almost wholly on the milk of camels, fresh or soured. On this diet they enjoy excellent health, display great vigour and reach advanced ages. Riley estimated that some of the old men must have lived for two to three hundred years. No doubt these figures are much too high, but it is probable that the Arabs Riley encountered lived really unusually long. Mr. Wales has examined Riley’s work critically, and is of the opinion that that author was a well-informed, sagacious and conscientious observer. M. Grigoroff, a Bulgarian student at Geneva, has been surprised by the number of centenarians to be found in Bulgaria, a region in which yahourth, a soured milk, is the stable food. Some of the centenarians, described by M. Chemin in his memoir, lived chiefly on a milk diet. Marie Priou, for example, who died in the Haute-Garonne in 1838 at the age of 158 years, had lived for the last ten years of her life entirely on cheese and goat’s milk (_op. cit._ p. 100). Ambroise Jantet, a labourer of Verdun, who died in 1751 at the age of 111 years, “ate nothing but unleavened bread and drank nothing but skimmed milk” (p. 133). Nicole Marc, who died aged 110 years, at the chateau of Colemberg (Pas-de-Calais), a hunch-back and cripple, “lived only on bread and milk-food. It was only towards the end of her life and after much persuasion that she took a little wine” (Chemin, p. 139). I owe to the kindness of M. Simine, an engineer in the Caucasus, the following communication, taken from the newspaper _Tiflissky Listok_, Oct. 8th, 1904. “In the village of Sba, in the district of Gori, there is an old Ossete woman, Thense Abalva, whose age is supposed to be about 180 years (?). This woman is still quite capable and looks after her household duties and sews. Although she is bent, she walks firmly enough. Thense has never taken alcoholic liquors. She rises early in the morning, and her chief food is barley bread and butter milk, taken after the churning of the cream. Butter milk is a liquid containing very many lactic microbes.