168 



forms its sheath, form a complete tube, admirably suited for 

 the conveyance of fluid along it. When the spine is driven 

 with force some distance into the flesh, the integument which 

 covers it will yield to the pressure of the wounded parts, 

 and be thrust downwards towards the base of the spine ; the 

 gland must in consequence be squeezed with some violence 

 between the hard bony part of the spine and the integument 

 which covers it. The necessary effect would be to expel the 

 contents of the gland into the bony channel ; but whether this is 

 effected by a rupture of its structure, or whether there are val- 

 vular openings which allow of the escape of the fluid, is more 

 than I can determine : nature very seldom adopts the former 

 method, though some observers have stated that the solitary 

 glands of the human intestine consist of sacs, the secretion 

 within which finds an exit by their rupture, the openings 

 subsequently healing. 



The Trachinus being furnished with this apparatus, the 

 mystery respecting the way in which it inflicts its sting becomes 

 less obscure ; the end being effected by means quite as well 

 adapted to the degree of injury it has to inflict as in other 

 venomous creatures. 



I trust that, although further investigation may probably 

 bring out some additional details of its structure, most of the 

 essential requisites have been demonstrated to prove that the 

 Trachinus has a glandular poison apparatus, and, if so, it 

 swells by an unit the vast number of facts which go to prove 

 the beautiful and fertile resources of nature, and the wonder- 

 fully varied means which she adopts for the accomplishment 

 of similar ends. 



