126 EVENINGS AT THE MICROSCOPE. 



their will. But each lancet has a singular projection 

 from its back, which appears to act in some way as a 

 guide to its motion, probably preventing it from slipping 

 aside when darted forth, for the bulbous part of the sheath, 

 in which these projections work, seems formed expressly 

 to receive them. 



Thus we see an apparatus beautifully contrived to enter 

 the flesh of an enemy : the two lancets finely pointed, 

 sharp- edged, and saw-toothed, adapted for piercing, cut- 

 ting, and tearing ; the reversed direction of the teeth gives 

 the weapon a hold in the flesh, and prevents it from being 

 readily drawn out. Here is an elaborate store of power 

 for darting them forth in the numerous muscle-bands; 

 here is a provision made for the precision of the aim ; 

 and, finally, here is a polished sheath for the reception of 

 the weapons and their preservation when not in actual 

 use. All this is perfect, but something still was wanting 

 to render the weapons effective, and that something your 

 experience has proved to be supplied. 



The mere insertion of these points, incomparably finer 

 and sharper than the finest needle that was ever polished 

 in a Sheffield workshop, would produce no sensible result 

 on our feelings ; and most surely would not be followed 

 by the distressing agony attendant on the sting of a 

 bee. We must look for something more than we have seen. 



We need not be long in finding it. For here, at the 

 base of the sheath, into which it enters by a narrow neck, 

 lies a transparent pear-shaped bag, its surface covered all 

 over, but especially towards the neck, with small glands 

 set transversely. It is rounded behind, where it is en- 

 tered by a very long and slender membranous tube, which, 

 after many turns and windings, gradually thickening and 

 becoming more evidently glandular, terminates in a blind 

 end. 



This is the apparatus for preparing and ejecting a 

 powerful poison. The glandular end of the slender tube 



