■78 



RECEEATIVE SCIENCE. 



burning pain, wliicli is instantaneously felt, 

 and is continued for some length of time after 

 the wound has been inflicted. If the plant is 

 carefully examined, it wiU be seen that it is 

 clothed aU over with simple hairs; but 

 amongst these hairs are scattered a greater or 

 less number of other and larger ones, which 

 are swollen at the base. If one of these is 

 removed from the stem with the point of a 

 sharp instrument, and placed under the mi- 

 croscope, it wiU be seen as represented in 

 the accompanying illustration (Fig. 1). The 



Fig. 1. 



Fia. 2. 



upper sharp-pointed process is a hollow tube 

 filled with a pellucid fluid, which is secreted 

 by a little gland at the base of the dilated 

 cellular receptacle, and is there held in re- 

 serve for use. It will thus be observed what 

 an admirable though simple contrivance of 

 defence this sting is; for, if the slightest 

 pressure is made upon the tube or base of it, 

 the fluid which it contains is forced through 

 the opening at the apex, where it is so finely 

 pointed that it readily enters any soft sub- 

 stance, such as the stin, and then, from the 

 acrid nature of the fluid (called by chemists 



formic acid) which is pressed through, pro- 

 duces immediately that pain and burning 

 sensation which is experienced. All the 

 species of the nettle are furnished with these 

 stings, but the poison of some of them is 

 much more virulent than others. 



The difference between the sting of the 

 Iiettle and that of insects, such as the bee 

 and the wasp, is so remarkable, that we shall 

 do well in our rambles to consider it, and 

 ponder over the wonderful adaptation of tlie 

 means used to attain the purposes for which 

 each is made by Jlim who made all things 

 perfect. 



That very busy, active, little insect, the 

 common wasp, which by many people is 

 looked upon with fear and dread, is not as 

 quarrelsome an insect as is generally sup- 

 posed, but is usually harmless unless dis- 

 turbed in its work, or in any way provoked ; 

 but when it is enraged it becomes pugnacious 

 and revengeful, and uses the formidable wea- 

 pon with which it is furnished with great 

 agility. If we capture one of these insects, 

 and, after having killed it, remove the last 

 ring of the body together with the sting, and 

 carefully separate the surrounding parts from 

 it, it will be seen, under a high magnifying 

 power, to be formed of a long taper-pointed 

 process, furnished at the base with cells and 

 glands, and on each side arise jointed arms, 

 the end joints being covered with hairs 

 (Fig. 2). The sting will be seen to be 

 flattened towards the point like a minute 

 dagger, one edge being simple and cutting, 

 the other serrated with eight to ten sharp- 

 pointed teeth like a saw, having the points 

 towards the base ; a little below the apex is 

 the opening into a tube, which, runs the 

 whole length of the dagger, and communi- 

 cates with a receptacle at the base, where the 

 glands are which secrete the poisonous fluid. 

 The opening into the tube below the apex is 

 protected by another serrated process, which 

 seems to act as a valve, and allows the escape 

 of the fluid, but protects the aperture, and 



