There is no doubt whatever that the new and entirely distinct Brünn race penetrated the Danubian region at this time, but there is no evidence from skeletal remains that it reached France. It is quite possible that some of the flint workers adept in the Solutrean 'retouch' migrated into the far western stations of Dordogne, bringing with them their beautiful technique, but without leaving traces of their skeletal remains through ceremonial burial. This unsettled problem affords one of the many reasons why the anatomy of all the Upper Palæolithic men of western Europe should be most carefully studied and compared. Another mystery of Solutrean times is the arrest of the artistic impulse which had animated the Crô-Magnons throughout the entire Aurignacian. Evidences of artistic work in Solutrean times are very rare, and some drawings which have been attributed to the Solutrean, as at Altamira, have now been referred to the Magdalenian. Is it possible that the Crô-Magnon race for a time suspended its artistic endeavor only to renew it under the different conditions of environment of Magdalenian times? Unfortunately, the Solutrean burials afford very little evidence on this point. One interpretation which may be offered is that the Solutrean was evidently a period of open-air life, and that the new implements of the chase of Solutrean type absorbed the industrial energies of these people, for the weapons were fashioned in enormous numbers. Consistent with this theory of climatic influence is the fact that the return of the severe climate of Magdalenian times, which crowded the men again into the shelters and grottos, was accompanied by a renewal of the artistic development continuing from the point where it had been interrupted in closing Aurignacian times. That Aurignacian and Magdalenian art is the work of one race there can be no question whatever; that this race was the Crô-Magnon is now absolutely demonstrated.