60 Right foot. _Idem_ 160 61–70 Hands and feet of lower animals, showing papillary ridges 161, 163–166, 168 71 Flexures on palm of right hand. Drawing made from impression 171 72–79 Flexures on hands and feet of various lower animals 172–175 80 Drawing of flexures of sole of foot of man, young adult 176 CHAPTER I. FROM KNOWN TO UNKNOWN Upward--still upward--still upward to the highest! Such is the claim of modern man for the story of himself and the lower inhabitants of the globe. The zoologists have gone so far as to confer upon him the surname Sapiens--Homo Sapiens. Learned indeed he is, and heir of all the ages, but whether or not his assumed surname be warranted the doctrine of descent with modification can never again be questioned. The work of Darwin was crowned when he compelled a general acceptance of that doctrine, and now the Descent of Man and the Ascent of Man are equivalent terms for a natural process which has converted man from a thing to a person, and is the foundation of all modern thought. The biologist works secure in the knowledge that he is studying some portion of a chain of life stretching back for incalculable ages, and is not careful to produce those missing links demanded by the once formidable foes of his fundamental principle. Haeckel may announce that Pithecanthropus Erectus of Dubois is truly a Pliocene remainder of that famous group of highest Catarrhines which were the immediate pithecoid ancestors of man. This may or may not be true, but if true it makes the descent of man from a lower stock none the surer, the increasing verification of which is not found to rest on missing links. Many of the discoveries of modern science are made by proceeding from known phenomena to the unknown, or, more precisely, from the well-known through the little-known to the hitherto unknown. As to the validity of knowledge it is enough to say this--and pass on--_all our knowledge is provisional and imperfect, and much of our ignorance is as transient as ourselves_.