Animal Galls. 427 



the egg is not attended by much pain, unless, as he adds, 

 some very sensible nervous fibres have been wounded. 

 According to this view, we must not estimate the pain 

 produced by the thickness of the instrument ; for the sting 

 of a wasp, or a bee, although very considerably smaller than 

 the ovipositor of the ox-fly, causes a very pungent pain. It 

 is, in the latter case, the poison infused by the sting, rather 

 than the wound, which occasions the pain ; and Vallisnieri 

 is of opinion that the ox-fly emits some acrid matter along 

 with her eggs, but there is no proof of this beyond con- 

 jecture. 



It ought to be remarked, however, that cattle have very 

 thick hides, which are so far from being acutely sensitive of 

 pain, that in countries where they are put to draw ploughs 

 and waggons, they find a whip ineffectual to drive them, and 

 have to use a goad, in form of an iron needle, at the end of a 

 stick. Were the pain inflicted by the fly very acute, it would 

 find it ne^xt to impossible to lay thirty or forty eggs without 

 being killed by the strokes of the ox's tail; for though 

 Vallisnieri supposes that the fly is shrewd enough to choose 

 such places as the tail cannot reach, Reaumur saw a cow 

 repeatedly flap its tail upon a part full of the gall-bumps ; 

 and in another instance he saw a heifer beat away a party 

 of common flies from a part where there were seven or eight 

 gall-bumps. He concludes, therefore, with much plausi- 

 bility, that these two beasts would have treated the ox-flies in 

 the same way, if they had given them pain when depositing 

 their eggs. 



The extraordinary effects produced upon cattle, on the 

 appearance of one of these flies, would certainly lead us to 

 conclude that the pain inflicted is excruciating. Most of our 

 readers may recollect to have seen, in the summer months, a 

 whole herd of cattle start off across a field in full gallop, as 

 if they were racing, their movements indescribably awkward 

 their tails being poked out behind them as straight and 

 stiff as a post, and their necks stretched to their utmost 

 length. All this consternation has been known, from the 

 earliest times, to be produced by the fly we are describing. 



