No. 630] HUMAN MORTALITY BATES 



37 



B. Mesoderm— Here the figures of Table XII were 

 reached by the following process. First, the totals of 

 Table I (circulatory system), Table III (sex organs), 

 and Table IV (kidneys), were added together, these 

 being obviously in general mesodermic. From the total 

 so obtained was subtracted item 124 of Table IV (dis- 

 eases of the bladder) since the lining epithelium, the most 

 vulnerable part pathologically, is endodermic in origin. 

 For the same reason item 125 of Table IV (diseases of 

 the urethra) was next subtracted. To the result so ob- 

 tained was added {a) the total of Table V (skeletal sys- 

 tem) and item 52 (Addison's disease) from Table IX, 

 these representing organs mesodermic in origin; (b) 

 0.04 of the rate under item 41 of Table VI (cancer of 

 peritoneum) ; (c) item 117 (simple peritonitis) ; (d) item 

 93 (pleurisy). The pleura and peritoneum are meso- 

 dermic structures and therefore clearly belong here. The 

 final totals reached after the above described process are 

 those which appear under "Mesoderm" in Table XII. 



Up to this point in the argument it has been assumed, 

 without discussion, that all the items in Table VII (the 

 nervous system and sense organs) go with the ectoderm. 

 There is, however, another point of view possible here, 

 which may be stated in the following way. Cerebral 

 hemorrhage and apoplexy (item 64) and softening of 

 the brain (item 65) are brain conditions brought about 

 by a precedent functional breakdown of a part of the 

 vascular system, namely the terminal arteries of the 

 brain. Cerebral hemorrhage is due to the rupture of an 

 artery or arteries in the brain, and may in and of itself 

 be a sufficient cause of death, just as would be a hemor- 

 rhage due to rupture of an artery in any other part of 

 the body. So far as anything now known can tell us, this 

 fatal accident is as likely as not to occur in a brain of 

 which the nerve cells (of ectodermic origin) are perfectly 

 sound organically. Should such a death be charged 

 against the ectoderm? The case is at least open to 

 question. 



