2.8o 



THE QUARTERLY REVIEW OF BIOLOGY 



are observable in the proportionate mor- 

 talities of ecto, meso, and endodermal 

 organs before man and preventive medi- 

 cine are reached. So perhaps this art and 

 science has only altered the course of 

 evolutionary events quantitatively, and 

 not qualitatively. 



In conclusion I should like to say that 

 no one can possibly recognize more clearly 

 than I do the shortcomings of the data 

 used in this discussion, including those 

 for man as well as those for the lower 

 animals. The results can at best be re- 

 garded only as suggestive, and not as 

 probative. But, considered simply as 

 description, they nevertheless do adum- 

 brate another, and, so far as I know, new 

 example of the "order of nature." It 

 may be that the biological philosophy 

 upon which the figures of mortality are 

 here arranged is not the one of maximum 

 heuristic value. But at least the system 

 upon which the mortality data are here 

 arranged is rational and consistent. No 

 other system, actually in use, for classi- 

 fying the pathologically recognized and 

 statistically recorded causes of death can 

 lay any claim to consistent rationality. 



The official "International List" for the 

 classification of the causes of death shifts 

 its basis, within its titles, with complete 

 casualness and abandon between etiology, 

 organology, embryology, and mere symp- 

 tomatology. As was recently (i) pointed 

 out in The Lancet: "The useful definition 

 of a disease may be aetiological — e.g., 

 typhoid fever — or anatomical — e.g., cir- 

 rhosis of liver — or purely symptomatic — 

 e.g., epilepsy; all such criteria are, in the 

 final sense, provisional, but they do very 

 well in practice." So they do. But from 

 the viewpoint of logical classification of 

 all mortality nothing is gained by mixing 

 these different bases in the same classifica- 

 tory scheme. 



The further the present rational and 

 consistent system of studying compre- 

 hensively the biology of human mortality 

 is carried, and we have accumulated a 

 large amount of work in this direction as 

 yet unpublished, the more does it appear 

 to justify itself as a method of research 

 on an extraordinarily complex and diffi- 

 cult problem of biology. No further 

 claim on its behalf "need be made at this 

 time. 



LIST OF LITERATURE 



i. Anonymous. Nomenclature. The Lancet, Jan- 

 uary z8, 192.8, pp. 194-195. 



x. Fox, H. Disease in Captive Wild Mammals and 

 Birds. Incidence, Description, Comparison. 

 With a Foreword by Charles B. Penrose, M.D. 

 Philadelphia (J. B. Lippincott Co.). No date 

 (Copyrighted 192.3). Pp. vii + 665 + 3 

 unnumbered. 



3. Laycock, T. Clinical lectures on the physio- 



gnomical diagnosis of disease. Delivered at 

 the Royal Infirmary, Edinburgh. Med. Times 

 and Gaz., Vol. I for 1862., pp. 1-3; 51-54; 101- 

 103; 151-154; 2.05-2.08; Z87-2.89; 341-344; 449- 

 45*; 499-5°^> 551-554; 635-637. 



4. Lucas, N. S. Report on deaths which occurred 



in the Zoological Gardens during 192.0. Proc. 

 Zool. Soc. London, 192.1, pp. 179-181. 



5. Lucas, N. S. Report, etc., during 192.1. Ibid., 



192.2., pp. 181-^.83. 



6. . Report, etc., during 192.Z. Ibid., 19x3, 



pp. 12.5-12.8. 



7. . Report, etc., during 1913. Ibid., 192.4, 



pp. 2.93-196. 



8. Pearl, R. Certain evolutionary aspects of 



human mortality rates. Amer. Nat., Vol. 54, 

 pp. 5-44, 19Z0. 



9. . The Biology of Death. Philadelphia 



(Lippincott), 19ZZ. Pp. Z75. 



Studies in Human Biology. Baltimore 



(Williams & Wilkins Co.), 1914. Pp. 653. 



