14 ILLUSTRATIONS 



FIG. PAGB 



23. Comparing the expectation of life of the population of the Roman 



provinces Hispania and Lusitania with that of present day 

 Americans 91 



24. Comparing the expectation of life of the population of the Roman 



provinces in Africa with that of present day Americans 92 



25. Showing Pearson's results in fitting the d x line of the life table with 



5 skew frequency curves 95 



26. Showing the relative importance of the different organ systems in 



human mortality 108 



27. Diagram showing the specific death rate at each age for deaths from 



all causes taken together 116 



28. The specific death rate at each age from breakdown of the circulatory 



system, blood and blood forming organs 118 



29. The specific death rate at each age from breakdown of the respira- 



tory system 120 



30. Specific death rates at each age from breakdown of the primary and 



secondary sex organs 125 



31. Specific death rates at each age from breakdown of the kidneys and 



related excretory organs 127 



32. Specific death rates at each age from breakdown of the skeletal and 



muscular systems 128 



33. Specific rates of death at each age from breakdown of the alimentary 



tract and associated organs of metabolism 129 



34. Specific death rates at each age from breakdown of the nervous sys- 



tem and sense organs 130 



35. Specific death rates at each age chargeable against the skin 132 



36. Specific death rates at each age from breakdown of the endocrinal 



system 133 



37. Specific death rates from all other causes of death not covered in the 



preceding categories 134 



38. Percentages of biologically classifiable human mortality resulting from 



breakdown of organs developing from the different germ layers. . . 140 



39. Specific death rates in males according to the germ layer from which 



the organs developed 144 



40. Specific death rates for females 146 



41. Survival curves of members of the Hyde family (Plotted from Bell's 



data) 153 



