Then as the system was found to work so well in these cases it was introduced into the prisons, each new-comer being made to sign the register with the finger. The official visitors had thus the means of satisfying themselves as to the identity of each inmate of the prison. Although Sir William Herschel tried to obtain permission to extend the use of the finger-print identification still further, his attempts did not meet with success. About the same time that Sir William Herschel published the account of his system a suggestion was made to register the Chinese in California by a similar process, but nothing was done in the matter. There have also been occasional applications of the method to prevent forgery, as, for instance, in 1882 in the payment orders signed by Mr. Thomson of the American Geological Survey, upon which, as a safeguard, he made the imprint of his own finger. It is to Sir William Herschel, however, that the credit is due of having established the first modern systematic process of registration of individuals by means of finger impressions. According to Dr. Faulds, the Chinese from time immemorial have caused their convicted criminals to make impressions of their finger-tips as a record, but he gives no details of their system of classifying the prints, if such exists. The curious markings upon which are based these systems of identification are not confined to the human race, but are also shown by monkeys and to a less pronounced extent by other animals. The pattern upon the surface of the skin upon the palms of the hand and soles of the feet is formed by the arrangement of what is known as the papillary ridges. It is readily recorded by carefully coating the finger-tips with a fine layer of printing or ordinary ink and pressing them upon paper so as to leave an imprint of the markings upon the finger. The uses of these ridges is to assist the delicacy of touch, and also to excrete perspiration through the minute pores with which they are covered. The effect of rough work upon the ridges is to increase their height, and eventually they may become covered up by the horny accretions known as callosities. On the other hand, the ridges upon the palms of people who do very little manual labour are much less apparent, and when the skin is thin are very low. Hence, in the hands of bedridden invalids there is only a slight development of the ridges. Several circumstances may lead to a temporary obliteration of the ridges, such as, for instance, the constant puncturing of the skin by the head of a needle in sewing, and the imprint of the forefinger of a tailor will therefore often present a very characteristic mottled appearance.