1902.] 



KNOWLEDGE 



145 



ILLUSTRATED MAGAZINE 



iSCiEPEJLiTERATtMAM^ 



Founded by RICHARD A. PROCTOR. 



Vol. XXV.] LONDON : JULY, 1902. [No. 201. 



CONTENTS. 



M.\x 

 IV.— The 



By K. J. 



A Chrvrt of the Human Hair Streams, showing their 

 Lineage and History. l!v Waltkh Kihd, m.d., f.z..s. 

 (Ilhslrated) 



Fore legs and their Uses. Bv E. .V. Bnr.EK, ii.v., B.sr. 



Ulii'slraled) '. _ ... 



A New Algol Variable. + 43' 4101. By Edwakj) C. 



I'n'KKiiiSc: 

 Astronomy without a Telescope. XV. -New Stars. 



Hy E. Waltkr ^rA^■^■DER, f.k.a.s. (Illustraled) 

 Distant Worlds. I. — A Review of some Recent Studies 



in Stellar Distribution. By I'. Eastox 



The -America" Nebula in Cygnus. By Br 



\V..I.K. {Pit,/,) ' 



The Use of Hand Telescopes in Astronomy. 



Stars. By Cecil Jackson. {Illustrated) 

 Letters : 



I'hK VlSlBII.ITV OF THE CliESCEN'T OF TeNUS. 



Ryi.k, .M.I). Xote by E. \Valtek Maunder 



The Date op Stonehkngk. By A. Fowier 



The SrN Pit.r.AR hf March 0. By E. J. Robbbts. 

 Niite by K. Walter AfArxDER... 

 British Ornithological Notes. Conducted by W. P. 



I'VCBAFT, A.L.S., F.Z.S., M.B.O.U. 



Notices of Books 



liiiiiKs Reiki vi;i) 



Notes 



Studies in the British 



Offspring of Ferns. 



(Illu.Klrated) 



Microscopy. Conducted by M. I. Caoss 



Notes on Comets and Meteors. By W. F. Drnbino 



F.B.A.S 



The Face of the Sky for July 



P.B.A.8. (lllustratid.) 



Chess Column. By C. D. Locoes, b.a. 



Flora IV.— The Protean 

 By K. Llotd Praeger, b.a. 



Bv W. Shackleton, 



145 

 Its 

 151 

 152 

 154 

 156 



isr, 



158 

 158 



1.58 

 159 

 160 

 160 



HU 

 165 



166 

 167 



A CHART OF THE HUMAN HAIR-STREAMS, 

 SHOWING THEIR LINEAGE AND HISTORY. 



Cy Wai.tkr Kidd, m.d., f.z.s. 



The interrogation of Nature is the richest seed-plot of 

 science, and those who t-uJtivate it are rewarded in due 

 tiini' if only their foundations be " well and trulv laid." 

 Whatever the answers may be, they will never be other 

 than true, and we must needs abide by the result of our 

 iuterro.ffation. No <*raeles are delivered by Nature's voice, 

 rather does she teach by the Socratic method of questioning,' 

 her learners. Thus it is that, since the f;enius oi Hutton 

 op^'ned up the way into the new world of geoloL,'v, tlnTe 

 are geological problems staring us in the face as we ])ursue 



our way on tliis planet, some inviting or compelling 

 emiuiry, some suggesting complicated and, perhaps, hope- 

 less study. It is not less so with biology, which a greater 

 than Hutton has illuminated, and where still the unknown 

 but knowable meets the naturalist on every hand. 



To the simpler class of problems belong those facts of 

 the direction of hair on the human body, open to the study 

 of most- of us on our own persons or on that oi any young 

 hairy subject. Those who have not looked particularly 

 into the matter are not aware that, in addition to the well- 

 known hairy regions, every inch of the human skin is clad 

 with tine hairs, except the palms of the hands, soles of the 

 feet, third phalanges of the fingers and toes, and one or 

 two other small areas. The character of this growth 

 varies from a covering of hairs, so minute that a good 

 lens is needed for their detection, to a profusion of long 

 hair of a Simian character, reaching its maximum in the 

 Ainu or hairy aborigines of Jajian. 



It is agreed to look upon this hairy covering as a vestige 

 of one which was of use to man's hairy, arlwreal, ape-like 

 ancestors, and to consider it as in process of disap])earance. 

 Whatever view we may take of its value, it cannot but be 

 subject to natural laws, and the canons of investigation 

 applied to other facts of Nature must be applied in this 

 small instance also. 



The rate of growth of the human hair, on the head at 

 least, is an inch in two months, and it is probably less on 

 the general surface of the body. 



The hairs are inserted in the skin at an acute angle on 

 every part of the body except the eyelids, where they are 

 at right angles to the surface, and wherever they are 

 found the hair-tracts have a constant direction for that 

 region. This sloping direction of hair is common to 

 nearly all lower animals, the mole being tlie most marked 

 exception, and the question cannot but suggest itself : Is 

 this slope adapted to the needs of the animal or man, or is 

 it adapted hij their habits? This debatable point cannot 

 be dealt with here. 



It is proposed here to study the direction of the human 

 hair-streams and the causation of their various peculiarities. 

 Broadly speaking these streams, according to their range, 

 show two things about man : first, what he has been ; 

 secondly, what he has done ; or, in other words, his 

 ancestry and his habits of life. 



The point which strikes one first in examining the chart 

 of these hair-streams is the very complicated direction 

 taken by them on the head, neck, and trunk, and on the 

 upper extremity, and the equally marked simplicity of the 

 direction of those on the lower extremity. Certain of 

 the former literiillv demand enquiry as to their cause, on 

 the sound principle that every phenomenon in Nature is to 

 be looked ujion as capable of explanation, whether by the 

 light of present, knowledge, or by future methods of 

 discovery. It is not necessary to employ hypothesis at all 

 extravagantly or to wait indefinitely for further light in 

 explaining most of these peculiarities in question. They 

 may be open to explanation by one of three hypotheses :— 



1. They may have been created with the rest of man's 

 jihysical frame, as an adaptation to his habits or certain 

 of his needs. This view will hardly commend itself in the 

 light of present knowledge. Apart from other reasons, 

 the direction in which the human hair slopes in the greater 

 part of his body is immaterial to his comfort or well-being. 



2. Adaptation and natural selection in the struggle for 

 life might help us. Here, again, the question of utility is 

 involved if such views are to be maintained. It is strange 

 to find such a statement as the following in an important 

 work for students on Physiology liy Mr. Leonard Hill, 

 who says without any reserve : " The fine hairs on the 

 body and limbs of man are arranged, as in the monkey, 



