148 EVENINGS AT THE MICROSCOPE 



in any part, but simply to lie in its groove; their basal 

 portions pass out into the body behind the sheath, where 

 you see a number of muscle-bands crowded around them: 

 these, acting in various directions, and being inserted into 

 the lancets at various points, exercise a complete control 

 over their movements, projecting or retracting them at 

 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 spears finely pointed, sharp- 

 edged, and saw- toothed, adapted for piercing, cutting, and 

 tearing; the reversed direction of the teeth gives the weap- 

 on a hold in the flesh, and prevents it from being readily 

 drawn out. Here is an elaborate store of power for the 

 jactation of the javelins, in the numerous muscle -bands; 

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

 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 intromission of these points, incomparably 

 finer and sharper than the finest needle that was ever 

 polished in a Sheffield workshop, would produce no result 

 appreciable to 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. 



