14 NATURAL HISTORY ESSAYS 



sharp edges of the upper incisors fit neatly into a 

 hollow in the lower jaw, just as the blade of a penknife 

 sinks into its sheath. The mouth of the vampire is a 

 veritable case of surgical instruments, keen-edged if 

 not aseptic. As regards the mode of action, it has 

 been established that the bat rasps the skin rather 

 than bites it, and thus planes off a minute shaving 

 and causes the blood to ooze from the capillaries. It 

 has also been thought that the animal uses the sharp 

 canines as augers, boring gradually deeper as it 

 flutters round and round ; but this requires confirma- 

 tion. The toes and nose in man and the withers 

 and haunches in cattle appear to be the usual points 

 of attack. 



A remarkable statement as regards the vampire, 

 namely, that it is difficult to stop the bleeding set up 

 by it, offers an opening to any naturalist keen on 

 original research. Mere capillary oozing can usually 

 be arrested by firm pressure on the part; hence per- 

 haps there is some haemolytic constituent in the bat's 

 saliva which prevents the formation of a clot. At 

 any rate the pharynx of the leech formerly used in 

 medicine contains such an agent, which can be ex- 

 tracted by chemical means, and even as a pharma- 

 ceutical preparation will effectually hinder the 

 coagulation of fresh-drawn blood placed in a test- 

 tube. That such a constituent should exist is 

 reasonable enough, for it is of the utmost importance 

 to the bat that its food should be absolutely fluid; its 



