174 EVENINGS AT THE ISnCKOSCOPE. 



is cut awaj, so as to serve as a sheath for the tongue, 

 which oi'dinarily lies "svitliin its concavity. 



I scarcely know whether this apparatus is not more 

 wonderfully delicate than auj Ave have examined ; — 

 even than that of the Flea. And how eflective it is 

 you doubtless well know ; for when the array of lancets 

 is introduced into the flesh, vou are aware tluit a tumour 

 is left, which by its smart, itching, and inflammation, 

 causes much distress, and lasts man}' hours. This effect 

 is probably produced partly by the deep penetration of 

 the instruments, — for they are fully one-sixth of an inch 

 in length, and they are inserted to their \Qvy base, — 

 and partly by the injection of a poisonous fluid, intend- 

 ed, as has been conjecturally suggested, to dilute the 

 blood and make it more readily flow up the capillary 

 tubes. Tlie channel through which this fluid is injected 

 is probably the tongue, which you see to be permeated 

 by a tube containing a fluid ; and the same channel 

 may aflbrd ingress to the diluted blood. 



The labium does not enter the wound. If vou have 

 ever had the philosophic patience to watch a gnat 

 while puncturing your hand, you have observed that 

 the knob at the end of the proboscis is aj^plied to the 

 skin, and that then the organ beiids with an angle 

 more and more acute, until at length it forms a double 

 line, being folded on itself, so that the base is brought 

 into close j^roximity to the skin. Meanwhile the lan- 

 cets have all been plunged in, and are now sunk into 

 your flesh to their very bottom, while the labhi^n^ 

 which formed merely the sheath for the whole, is bent 

 up upon itself, ready again to assume its straight form, 

 as soon as the disengaged lancets require its protec- 

 tion. 



