Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.2): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

646 EAIILY iilGUATION Climate, habits, and food operate to cause a considerable change in the form and size, though their permanent effect on the colour of the human race is slight. The effect of climate, considered alone, may be seen in the descendants of English families settled in some parts of North America, in Australia, or Van Diemen's Land ; countries where neither habits nor food differ much from those of England. We see there that our sturdy thick-set labourer's son becomes a tall lathy youth, though perhaps none of his family while in England exceeded the middle height : and not only does the form alter, but the gait and voice acquire peculiarities which mark the American born, the Australian, or the Tasmanian. Exposure to cold, wet, and wind, together with but little walking exercise, shortens the legs, and increases the stoutness of body, as may be seen in the Fuegian, the Esquimaux, and the Laplander, — in fishermen, sailors, coachmen, and others ; but, activity on foot, warmth, and a fine climate, have contrary effects, which may be shown by the youth above mentioned, by the African Negro, by the Indian, by the South Sea Islander, and others. Habits require httle notice, for we can hardly look around us without seeing many instances of faculties or forms altered in one way or other, by exercise or the want of it, or by certain customs : porters, smiths, dancers, grooms, jockeys, are remarkable instances. That food is a material agent in affecting the human form I think no one can doubt ; and when all three combine to cause alterations, how considerable must be the change effected. That colour may be altered a little by seclusion and particular diet, or by exposure to wind and sun, need not be remarked, except for the purpose of adding that a change so caused is not permanent, or transmitted to children, like peculiarity of form. The Otaheitans used to shut themselves up for a month at a time, and eat only par- ticvilar food, in order to become fairer ; yet their descendants are as dark at this day as their fathers were when Wallis first discovered them in 1786. I will now endeavour to point out those lines of communi- cation across the oceans which appear to me, ^as a seaman, the