OCR Text |
Show I . I 234: THE CRANIAL CIIARACTERISTICS proprcs du ncz tendon!, a so r lever davant,ago suivant los traits des individus ou des raccs." 77 Some physiologists have supposed that permanent modifications of cranial form are produced during sove1·c and prot.ractcd accouchernentB. Gall, long ag , rcfut d this notion, and CVCI'Y accouclteur has, in fact,, constant oppol'Lunitics of sat,isfying himself of tho untcnauiliLy of tlJis doctrine. It has more than once happened to me, as it nccef:lsarily do s to every physician engaged iu the pl'acticc of obHt Lrics, to witness a h ad, 1 ng compr sscd in a narrow pelvis, born wiLh th nose gr atly depressed, the iorchcau £1aLLCitcd, tho parietal bones ovcrridiug each other, and Lhc whole f:lkull completely wiredrawn, so as to rcscmulc some of the permanent deformations pictur d in the books; and yet., in a few days, Lhc i nhcrent last.i ·ity of tile bony caf:lc and iLs conLaincd parts has sufliccd to rcsLor iL to its natuL·aJ fol'm. But tl1 great objection to this opinion lies in tl1c fact of n conlol'mity between the cranial and pelvic typ s of a parLi ·ular race. Dlt. VnoLTCK, £ llowing up tl10 Sllggcstions of Camper and some other ob crv rs, relative to ccl'Lain peculiarities of tl1o negro pelvis, has demonstrated tl1c exist nco of a race-form for the pelvis as for th cranium. lie kts shown that tho form of th head is adnptc<l to tho p lvic passage which it is compelled to traverse in tho parturient n.ct, nnd that the pelvis, lil the skull, possessct:l its ra c-cl1aractcrs n.nd sexual distinctions, suflici ntlyw ll marked, cv nat the infantile po ·l1. As in th zoologi al series, we :find tllo omnium of t110 monkey c1iflcl'ing from that of tho animals below it, and approximating tho lwrnan type, so we find the pelvis pursuing tho same gradation, from Lhc Orang to tl1c Bof:ljieman, from the Bosjicman to the Ethiopian, from the Ethiopian to the Malay, and so on to the high caste WJ1iLo rae , where it attains its p rfcction, and is the farth st removed in form from that of tho oth r mammiform. I am aware that W EDER has aLLcmptcd to deny tho valnc of those observations, by showing that, although certain p lvic forms occur more frequently in some races than in oth rs, yet exceptions were found in the fact of tho European confoL·mation being occasionally encountered amono- other n.nd very different races. "This is not proving much," as D~ Gobineau acute!~ observes, "inasmuch as M. W ebcr, in spcaki ng of these cxcepL1ons, appears never to have ontcrLaincd the id a that thci L' peculiar conformation could only be the result of a mixt;re of blo d." 78 17 • Ea~ni eur loM D6formalions Artificiellos du Crfme, Pnr L. A. Oosso, do Oonllvo &c, Ptms, 1865. Published origino.lly as a contribution to tho ".Annates d' lJygiane Publigu: ce d !tftdrcinc Llgale," 2o s6rio, 1856, tomes III. ot, IV. c 18 Op. oit., t. 1, p, 108. OF THE RACJ~S OF MEN. 2~G In the study of cranial formA, sexual differences should not be overlook d. "The iemalo skull," says DAVJS, "except in races equally di:;tingui:;h d by forms strikingly impr f:lscd, docs not cx11ibit the gcntilitial <:l1arnct t'S emin •ntly." 79 IL is well kno,vn to the obsteLI'i •imt, that Lhc male skull, at birLh, is, on Lhc average, larger than the female. A complete hiHtory of the development of the human brain and cranium, in the difler lit races, would onsLiLutc one of the moAt valuable COlltrilmtions to anthroJ ol gy. S11ch a l1istory alone can determine tlto trn meaning of the val'ious appcaran •cs which Lheso part:; assum in th ir tmnsition from th ovum to the fn11y-d v lop d typical charactcl', and d monstraLc their as yet myf:ltcrions relations to tlt innrunel'ahle forms of life whic·h arc scaLt red over the surface of tl10 globe. To sn h a history must we look, also, for a solution of tl1c qu stion, as to wh th r ~he soft and pnlpy brain models at'OLmd its If its l1a1·c1 and resisting bony case, or, conversely, whether Lbis latter gives sl1apc to tl1 f, I'm r. Dtu·ing the firr:;t six weeks of emb1·yonic life, the brain, clotllcu in it. diff'•r·ent envelopes, xists without any bony investment, being Slll'I'Ound d externally with an cxtl' m ly thin, soft, and pliable cartilaginous m mhmnc, in which o. Rili.cation subs qn ntly takes place . Abont the eighth w ck, as shown by the invcstio·ations of Gall, th , ossi-fic points app a1· in this mcmbran , sending out div ro-ing raclji in cv r·y dire tion. As this delicate cartilaginous layer· is moulded nicely over th bnlin, th mir1l1tc specks of calcar ous matter, as they n,r d posit cl, mtiRt to some extent acquire tltc sam form as the brain. Whether tl1is b true t' not, thoro is a mttnifest adaptation between the brain and cmnium, the result of a hal'mony in gl'owth, inscpa1·ably connected with the action of one developing principle in the human economy. From thi:; iit t, :-tlonc, we might fhirly infer that differ·cn cs in the volume and confignmtion of a number of crania arc rr ncl'al indications of difFer n cs in the volume and confignration of their contained brains. One singl fact, among many others, proves this admirable lwrmony. lt is this: Th proccBH of ossification is at fil'st most mpid in the bonos composing the vault; but pl'escntly ceasing h t·c, it advances so 1·apidly in those of' the bnso and infc1·ior parLH generally, that at bi1'th tit base is solid and incomp1· ssiblc, thus pr t cLing fi·om pl' ssur the n rvons centre of respiration, which is at tlJis time fimter nnd better developed than the softer and less voluminous ecr brallobcs. Accot·diog to th emhryologic investigations of M. DE SERRES, of all brains, that of the high-caste European is the most complex iu 10 Op. cit., p. 6. J J' |