)n>? II. 



Manner of Development. 



33 



suc'^sive generations haying passed nearly their whole lives in 

 canoes, with their lower extremities motionless. Other writers 

 have come to a similar conclusion in analogous cases. According 

 to Cranz, 24 who lived for a long time with the Esquimaux, " the 

 M natives believe that ingenuity and dexterity in seal-catching 

 " (their highest art and virtue) is hereditary ; there is really 

 u something in it, for the son of a celebrated seal-catcher will 

 " distinguish himself, though he lost his father in childhood." 

 But in this case it is mental aptitude, quite as much as bodily 

 structure, which appears to be inherited. It is asserted that 

 the hands of English labourers are at birth larger than those of 

 the gentry. 25 From the correlation which exists, at least in 

 some cases, 26 between the development of the extremities and of 

 the jaws, it is possible that in those classes which do not labour 

 much with their hands and feet, the jaws would be reduced in 

 size from this cause. That they are generally smaller in refined 

 and civilised men than in hard-working men or savages, is certain. 

 But with savages, as Mr. Herbert Spencer 27 has remarked, the 

 greater use of the jaws in chewing coarse, uncooked food, would 

 act in a direct manner on the masticatory muscles, and on the 

 bones to which they are attached. In infants, long before birth, 

 the skin on the soles of the feet is thicker than on any other part 

 of the body; 28 and it can hardly be doubted that this is due 

 to the inherited effects of pressure during a long series of 

 generations. 



It is familiar to every one that watchmakers and engravers 

 are liable to be short-sighted, whilst men living much out of 

 doors, and especially savages, are generally long-sighted. 29 Short- 

 sight and long-sight certainly tend to be inherited. 30 The 

 inferiority of Europeans, in comparison w T ith savages, in eye- 

 sight and in the other senses, is no doubt the accumulated and 

 transmitted effect of lessened use during many generations ; for 

 Eengger 31 states that he has repeatedly observed Europeans, 



24 'History of Greenland,' Eng. 

 translat. 1767. vol. i. p. 230. 



25 ' Intermarriage.' By Alex. 

 Walker, 1838, p. 377. 



- 6 'The Variation of Animals 

 rider Domestication,' vol. i. p. 173. 



27 'Principles of Biology,' vol. i. 

 p. 455. 



28 Paget, ' Lectures on Surgical 

 Pathology,' vol. ii. 1853, p. 209. 



29 It is a singular and unex- 

 Dected fact that sailors are inferior 

 to landsmen in their meau distance 

 of distinct vision. I>r. B. A. Gould 



3 



(' Sanitary Memoirs of the War of 

 the Rebellion,' 1S69, p. 530), has 

 proved this to be the case ; and he 

 accounts -. for it by the ordinary 

 range of vision in sailors being " re- 

 " stricted to the length of the vessel 

 " and the height of the masts." 



30 'The Variation of Animals 

 under Domestication,' vol. i. p. 8. 



31 ' Siiugethiere von Paraguay,' 

 s. 8, 10. I have had good opportuni- 

 ties for observing the extraordinary 

 power of eyesight in the Fuegians. 

 See also Lawrence (' 1 ectures ot 



