HRDLKKA] PHYSIOLOGICAL AND MEDICAL OBSERVATIONS 159 



tliey no longor touch in thoir ii])j)ei' fourth in tlio median Hno, hut 

 leave a marked subpelvic s])a('e. No decisive evidence was obtained 

 as to hardening of the arteries; it is certainly not common. 



With a still further advance in age the sight and hearing get 

 weaker, the speech (mainly perhaps through the loss of teeth) becomes 

 less intelligible, and the mind enfeebled, while the skull shows signs 

 of absorption;" these signs are precursors of the nearing end. 



Several of the phases of senility were studied in detail, as iruiscu- 

 lar force, appearance of grayness, and baldness. The lack of proper 

 age records was again felt severely and can be replaced only by ap- 

 proximations. 



The data on muscular force were considered with that subject in 

 adults. It was there seen that a decline in force takes place in numer- 

 ous individuals even before 40, and is general and progressive after 

 that age. The same conditions obtain among whites. 



Grayness. — Special attention was paid to this subject in fourteen 

 of the tribes. A few gray hairs may now and then be seen on the 

 Indians even in advancing childhood, but these are due to abnormal 

 conditions affecting the individual follicles. Exceptionally the begin- 

 ning of real, progressive grayness will be met with in 3'^oung adults. 

 In general, however, the decoloration is slower and of a less degree 

 than in whites. There -are many old individuals in whom the hair 

 still retains in part the original color. In some of the old Indians 

 the hair is decolored irregularly, being gray and yellowish. The fol- 

 lowing data show the results of a direct examination in this line : '' 



a The signs of senility in the Indian skeleton are as follows: The skull shows a worn condition and 

 often extrusion (due to alveolar atrophy) of the remaining teeth, and absorption due to disappearance 

 of l>oth alveolar processes; rarely there is a characteristic bilateral antero-posterior depression over the 

 parietal bone at some distance from the median line, due to absorption of the diploe; and there is syn- 

 ostosis of sutures. In the rest of the skeleton may be seen a general lightening of the bones, with 

 thinning of the compact tissue; ossification of costal cartilages and ensifonn appendix; marginal 

 exostoses on long bones and especially on the vertebrae, and occasionally a fusion of vertebrae or 

 pelvic bones through the marginal exostoses. 



b Detail data in the Appendix. 



