The streams of his hair demonstrate two important facts about man: first _what he has been_; secondly _what he has done_, that is to say, his ancestry and habits of life, through an immense stretch of time. These stories in hair are the culmination of a large number of characters inherited and acquired, and their study in two selected regions of lemurs, apes and man will be pursued in this chapter on the lines which I laid down in Chapter VI. I have thought it well not to give any connected account of the rest of his hairy covering so as to concentrate attention on the two simplest and most striking regions. The charts of his hair-streams and those of the lemur and ape have been described with sufficient fulness elsewhere,[55] and no cartographer has hitherto sought to improve upon them. [55] _Direction of Hair in Animals and Man._ The back and the front surfaces of the trunk afford the two best and most instructive fields of study, for the forces which act upon them are of a simple kind, and may be traced upwards from the lemurs to man as in the case of the forearms. The three drawings (Fig. 41) represent the backs of a lemur, chimpanzee and man, most of the details of the hair being omitted and their place taken by thick dark arrows which show the line of the different hair-streams. This diagrammatic method will make any misunderstanding of the main facts impossible. The lemur has on the back of its neck a forward or headward slope of hair and this passes on to the head itself, and on the back of the trunk, as the arrows show, there is no departure from the normal arrangement of the lower mammals. The lemur, therefore, requires neither further description nor explanation. The ape shows no material change in this region from the arrangement of its lemur or monkey ancestor, in spite of the greater proportion of its life which is spent in the upright posture; indeed, this is what one would expect. Hair of the Back of Man. When the hair on the back of man is examined a remarkable change from the patterns of any of his known or supposed ancestors is found. It is by no means easy to trace the course of the hairs on the human back. A young, hairy and dark-haired person gives much the best field, and a lens may be necessary. In older subjects the hair is often so much worn away by friction that the direction can no longer be followed. Suffice it to say that the examination, though somewhat difficult, can well be carried out if the proper conditions are observed; and that it bears out the results which have come from the corresponding examination of infants. _The arrangement is congenital._