WHY WE GO GREY

Marlborough Express, Volume LX, Issue 229, 28 September 1926, Page 7

WHY WE GO GREY

' - - - • W - ^ — ; STORIES OF vSUDDEN BliANCTIING (»>- HAIR. Professor J. Arthur Thomson, writing in T.P.'s ahtl Casscll's Weckly, states that there are some remai-k-able instanoes of ihe sudden whitening of the hair in man. Historians tell us oi' oue of the kin,gs of Bavaria Avhose remorse for killing an innocent man was markecl by his turning gre.v in a single night. Very picturesque is the ease of a Swiss youth wbo let himself down by means of a ropc to an eagle's eyrie on a prbcipitous cliff. He wished to sccurc tlio young ones, iso be armed bimseif witb a cutlass to deal with the parent birds if they became aggressive, He secured the nestlings, but what be anticinated did actually occur, and in slashing at the parents he struck and nearly scvercd tho supporting ropc above his liead. During the int.cn al of elimbing un cautiousIv to thc snund part of the ronc his hair iurned grov. Somo Avould soathat it served him right. In any case, he scems to have bcen rather Briareus-liko as regards liands 1 INfarie Antionette Avns another instance of the sudden blanching of the hair in an emotional storm : at least so say the Iiistorv hooks. Other cases are cited hv Cnelius Rhodigenus and bv Nicolau s Florentinus. and a seientific discussion. of ihe subiect is given bv Laudois. He concludes that sudden blauchinu is due tr> the ranid evolution of gas-Vacuolcs in the corc and cortex of the hair. These vacuoles serve as reflecting surfaoes aucl mask the pigmeni which is still present. AVien ; hair turns sIoavIv grey there mav he an actual removal of rnVni^nt * and. according to Aletchnikoff this is effected bv the activitv of wanflering amoeboid cells or phnorocvtes. It is a weird oicture. that of the rnicrosfone sanoers and miners creeping un the core of the hair. engulfin"- a particle of nicrment. and rpmincr ffoAvn nfnin into the skin with their infinitesimal burdens. Tt sometimes happeus that individual hairs of a stoat or of a mountain hare hecome white, and this may he due to nhaaocytic activitv ; but the norma! winter whitening- of these and some other creatures is due to the new growth of a white snit, Avith gas-vacnolcs taking the place ot pigment. SimilarTv in normal old nce, the eoutinued crowth of ihe hairs sbows little or no nigment and a^ multitude of gas hubbles. In manA' animals at different- levels of organisation there is a remarkahle nower of quick color ehange, vehieh sometimes serves liko the rtossession of a Gyges' riug. The omiek chanre hecome practicallv invisible. Tn other eases the color ehange exnresses nervous excitement. and may have no more nrotective value than hlushing. This. it mav he uoted. is due to tho dilation of tlie minute hranchos of ihe superficial arteries when these are relieved from the control of the vaso-motor nerves that kcen them normally in a state of rvartial oontraction. The increased llow of hlood shows itself hv tho ehange of color in the skin, and this is hy no means always confined to ihe faee and neck. Tt is usoful iry keeo the nlienomenon of blnshimr in mind, for it relieves us from the taslc of discovering ai all costs somo utilitarian intorpretation of rapid color chan.ge in lower animals such as orustaceans and cut.tle tishes, (Iai fishes, and frogs. ehameleons, and other lizards. There is no douht that the color ehange has sometimes a protective value, piviog ihe crcature a cloak of invisibilitv. but this should he proved exnerimcntallv. not merely assumcd on a priori ground.