190 HEREDITY IN RELATION TO EUGENICS 



separate from the mainland, and even broad rivers; also 

 mountain ridges or heights of land. All such barriers re- 

 strain exogamy, or marriage outside the family, and favor 

 consanguineous marriage or endogamy. 



a. Barrier of Water. — Of oceanic islands the Canaries, 

 Azores, Bermuda, the Bahamas and the Lesser Antilles are 

 examples. In the case of the South Sea Islands the half 

 aquatic nature of the inhabitants has reversed the usual 

 order and made the sea a means of intercommunication. 

 On our own coast we have striking examples of semi-oceanic 

 islands with evidence of consanguineous marriage (Fig. 168). 



At Miscou Island on the Northeast coast of New Bruns- 

 wick there is said to be much intermarriage. The popula- 

 tion "is partly English and partly Arcadian French and 

 each race has kept pretty much to itself so they are closely 

 intermarried within the same race." 



The islands off the Maine coast show much consanguineous 

 marriage. Thus in Small's (1898) History of Swan's Is- 

 land it is stated that the amount of intermarriage of per- 

 sons of the same name in Mount Desert Island, Gott's 

 Island and Swan's and Deer Islands makes genealogy con- 

 fusing. For example, take the Gott family as shown in 

 Fig. 169; or a family from Swan's Island (Fig. 170). Even 

 more marked examples are furnished by outer Long Island 

 and the islands opposite Jonesport, Maine. 



One sees how little opportunity is afforded in such pedi- 

 grees for the coming in of new blood. Little wonder that 

 among these descendants of some ancestor who probably 

 carried inferior mentality are some intellectually dull ones. 



At western Martha's Vineyard Dr. Alexander Graham 

 Bell (1889, p. 53) has made a careful genealogical study of 

 the inhabitants. "I found," he says "a great deal of inter- 

 marrying and a great many consanguineous marriages." 

 Concerning this locaUty Dr. Withington (1885, p. 26) says: 



