THE DESCENT OR ORIGIN OF MAN 57 



while in two Europeans, measured at the same time, the 

 femora to the tibise were as 244 to 230; and in three Negroes 

 as 258 to 241. The humerus is likewise shorter relatively 

 to the forearm. This shortening of that part of the limb 

 which is nearest to the body appears to be, as suggested to 

 me by Mr. Forbes, a case of compensation in relation with 

 the greatly increased length of the trunk. The Aymaras 

 present some other singular points of structure, for instance, 

 the very small projection of the heel. 



These men are so thoroughly acclimatized to their cold 

 and lofty abode, that when formerly carried down by the 

 Spaniards to the low eastern plains, and when now tempted 

 down by high wages to the gold-washings, they suffer a 

 frightful rate of mortality. Nevertheless Mr. Forbes found 

 a few pure families which had survived during two genera- 

 tions, and he observed that they still inherited their charac- 

 teristic peculiarities. But it was manifest, even without 

 measurement, that these peculiarities had all decreased ; and 

 on measurement, their bodies were found not to be so much 

 elongated as those of the men on the high plateau: while 

 their femora had become somewhat lengthened, as had their 

 tibiae, although in a less degree. The actual measurements 

 may be seen by consulting Mr. Forbes's memoir. From 

 these observations, there can, I think, be no doubt that 

 residence during many generations at a great elevation 

 tends, both directly and indirectly, to induce inherited 

 modifications in the proportions of the body."* 



Although man may not have been much modified during 

 the latter stages of his existence through the increased or 

 decreased use of parts, the facts now given show that his 

 liability in this respect has not been lost; and we positively 

 know that the same law holds good with the lower animals. 

 Consequently we may infer that when at a remote epoch the 

 progenitors of man were in a transitional state, and were 



" Dr. Wilckens ("Landwirthachaft. Woohenblatt," No. 10, 1869) has lately- 

 published an interesting essay showing how domestic animals which live In 

 mountainous regions have their frames modified. 



