1 8 NATURAL HISTORY ESSAYS 



live on blood. One thus notes a curious paradox- 

 there are harmless vampires, just as there are flight- 

 less birds, and fishes which, like the African Periop- 

 thalmus, habitually leave the water for the shore. It 

 should nevertheless be borne in mind that of the very 

 numerous bats classed as vampires a few species may 

 occasionally vary their diet with blood : normally, 

 however, their food consists of fruit or of insects 

 taken on the wing. Insectivorous bats have a well- 

 developed steering membrane uniting the tail and 

 hindleofs into a kind of kite-rudder ; the true desmo- 

 dus, it w411 be remembered, has no tail at all and 

 scarcely any interfemoral membrane. 



In spite of its abundance no example of the true 

 vampire seems to have been brought alive to 

 England. There would appear to be little difficulty 

 in doing this, provided that the bats were accompanied 

 en route by living animals capable of acting as hosts. 

 The South American cattle trade would doubtless 

 admit of this, and the bats would certainly be an 

 interestinsT addition to the Zoolo^jical Gardens.-^ For 

 another reason also, the arrival of a boxful of these 

 desmodus would be very acceptable to English 

 naturalists ; for it would then be possible to carefully 

 and methodically search the salivary glands for any 

 ferment that might hinder the coagulation of blood. 



1 Since tlie viiinpire ranj^es to the very seashore fine healtliy specimens 

 might be obtained by travellers on the very point of departure for England. 

 A specimen was taken in 1847 at Valparaiso and another in the Baie de 

 Piscadoros, I'eru, on November 16, 1867. 



