OLD AGE. 58V> 



(lin-iiii!; (Miibi-yonic life tliat colls are produced with (he oreatesi 

 activity. Later on this proliferation becomes slower hiit it neverthe- 

 less continues to occur throughout the course of life. Hiihler attrib- 

 utes the (liffioiltv with which wounds heal in the a^ed, precisely to 

 the insufficiency of cellular production. Tie also thinks that the 

 reproduction of the cells of the epidermis which are to replace the 

 desiccated parts of the skin diminishes notably during old ag(>. 

 .According to this author it is theoretically easy to predict tlie 

 moment when culhdar nniltiplication in the epidermis must com- 

 j)letely cease; as the desiccation and desquamation of the sujx'i-ficial 

 parts continues without cessation it becomes evident that it nuist 

 finally result in the total disappearance of the epidermis. The same 

 rule is applicable, according to Bidder to the genital glands, the 

 muscles, and all sorts of other organs. 



These theoretical considerations do not, however, agree with well- 

 known facts which speak but little in favor of a general diminution 

 of cellular proliferation in old age. The hairs aiul the nails, which 

 are excrescences of the epidermis, keep cm growing throughout the 

 entire life, thanks to the reproduction of the cells which constitute 

 them. There is no arrest at all in the development of these parts 

 even in the most advanced age. Far from that. We know that the 

 hair that covers certain portions of the bodj^ increases in quantity 

 and length in the old. In certain inferior races like the Mongols, 

 the mustaches and the beard do not grow abundantly until advanced 

 life, while young people have but snuill mustaches and very little 

 or no beard. In women of the white race the same phenomenon 

 occurs. The delicate and almost imperceptible down that covers the 

 upper lip, the chin, and the cheeks of young women is transformed 

 into veritable hair which forms the nnistaches, beard, and whiskers 

 of old women. Doctor Pohl, a specialist in everything that concerns 

 the hair, measured the rai)idity of growth of hair under different 

 circumstances. He found that in an old man of Gl years the hairs of 

 the temples grew 11 nun. in a month. But these hairs, in the 

 same regions, in boys of from 11 to 15 years grew in the same time 

 11.8 nnn., which represents almost the same figure. 



There is therefore in the three subjects studied by Doctor Pohl no 

 considerable diminution in the cellular growth in the old, in spite 

 of the great difference in age. It is true that this observer showed 

 that the hair of a young man between 21 and 24 gi-ew at a rate of 15 

 mm. per month, Avhile in the same individual at the age of 61 

 years the rate lowered to 11 mm.; but this slowing down of the 

 'growth of the hair was only apparent. In fact, the first figures 

 related to hair from different regions of the hairy scalp, while the 

 second related only to the hair of the temples. Now it is well estab- 

 lished by Doctor Pohl himself that in the latter place the hair grows 



