the bahama islands 405 



Yellow Pevek. 

 We did not meet with a single case of yellow fever during our cruise among 

 the Bahama Islands. In fact, no cases of yellow fever have been reported in 

 the Islands for the last forty years. Mr. CoSin, however, in his investigation of 

 the mosquitoes found that the yellow fever mosquito, Stegomyiu fasciata, was 

 present in most localities where the Expedition stopped. The absence of yellow 

 fever, therefore, is not due to the lack of favorable conditions for spreading the 

 epidemic, but to the watchfulness of the authorities and the well organized 

 quarantine service. The only protection against this dread disease to the var- 

 ious communities living in the Bahama Islands is a prompt and complete isola- 

 tion of any eases of yellow fever which may in the future chance to appear in 

 their midst. 



POLYDACTYLISM. 



Although we only observed one instance of this interesting condition, we 

 learned that it was quite common in the Bahamas. The case we saw and 

 studied was that of a full-blooded negro, Samson Eooker (Plate LXXII, Fig. 1) 

 by name, who lived on the island of Andros. The interesting feature in his 

 case was the perfect symmetry of the right hand and foot, although the hand 

 possessed an extra little finger (Plate IjXXIX, Fig. S), and the foot an extra 

 little toe (Plate LXXVIII, Fig. 2). Indeed, so perfect was the formation of 

 the hand, that one would scarcely notice any abnormality unless the fingers 

 were actually counted. The left hand and foot showed only a "rather rudi- 

 mentary little finger (Plate LXXIX, Fig. 1) and little toe. At one of the 

 other islands we were informed that there was a man who had seven fingers on 

 one hand and a former resident of Hopetown, Abaco, the so-called " three 

 thumbed Jack," was celebrated from the fact that he had three thumbs on each 

 hand. 



Polydactylism, which is congenital in many cases, seems to be hereditary. 

 Most frequently the extra toes or fingers are placed symmetrically on both 

 hands and feet. Usually there is but a single digit on the side of the little 

 finger or toe, though more rarely the thumb, and much less often the great 

 toe is doubled. The development may be complete even to an extra metacarpal 

 or metatarsal bone, or it may be more or less imperfect, and is often little 

 more than a rudimentary nodule connected with the side of the phalanx. 

 When perfect, it is most often attached at a greater or less angle to the end of 

 the metacarpal or metatarsal bone of the normal finger or toe. At times the 

 connection with the hand or foot is by fibrous bone of varying length and 



