[45] Roy, D., Thèse de Paris, No. 110, 1910.

[46] Lancet, 1889, ii. 349.

[47] Weber, Hermann, On Longevity and Means for the Prolongation of Life, 1919, 5th edition, by F. P. Weber, London.

[48] Brownlee, J., The Use of Death Rates as a Measure of Hygienic Conditions, p. 51. Special Report Series No. 60. Medical Research Council, 1922.

[49] Savage, G., Memorial to Sir William Osler, vol. i. p. 247, 1919, New York.

[50] Butler, S., Evolution, Old and New, p. 380, 1911.

[51] Weber, F. P., Med. Press, London, 1920, N.S., cix. 271.

[52] Compare Fischer, Martin H., The Unpopular Review, 1919, ix. 323.

[53] Paget, J., “Errors in the Chronometry of Life,” in Studies of Old Case Books, p. 92, 1891, London.

[54] Osler and McCrae, The Principles and Practice of Medicine, p. 834, 1920, New York and London.