CURRENT NOTES. 229 



"Tha district referred to in. these notes lies between the Kaduna and 

 Kara Rivers ; Wushishi, on the opposite side of the Kaduna Eiver, being 

 the nearest town — an old war camp." 



A possible remedy for the Bots of Grastrophilus. 



M. P. Portier (C. R. Soc. Biologie, 1910, p. 1056) points out that 

 hitherto all attempts to destroy the bots of Gasfrophilus in the stomach of 

 the horse have failed. Such remedies as corrosive sublimate; salts of arsenic, 

 thymo], spirits of turpentine, tincture of pyrethrum, etc., have been used 

 with little effect, or have even proved fatal to the horse. 



He attributes these powers of resistance on the part of the larvse to the 

 possession of an extremely effective mechanism in the tracheal system, which 

 prevents the invasion of the body by poisonous liquids (see C. R. Soc. 

 Biologic, 1909, p. 568). So effective is this contrivance, that these larvae 

 have been placed for three or four hours in alcohol, spirits of turpentine, 

 corrosive sublimate, castor oil, etc.^ without being seriously affected thereby. 

 From his examination of the tracheal system, he concluded that a remedial 

 liquid to be effective must possess the following properties : — It must be 

 capable of moistening the chitin, which is a hydro fuge ; it must have a very 

 feeble surface tension, in order to prevent the phenomenon of gaseous 

 adsorption, which is so marked in these insects and which is so efficacious 

 a means of protecting the stigmata from the invasion of external liquids ; 

 and finally, it must possess these qualities in an acid, as well as a neutral, 

 medium. 



When almost on the point of abandoning his search for such a liquid, it 

 occurred to him that bile possesses all these properties ; and actual experi- 

 ment showed that when Gastrophilus larvae were placed in even a weak 

 solution of bile (1 per cent.), the liquid rapidly entered the tracheal system. 

 By adding suitable remedies to the bile, the largest larvas could be killed in 

 less than an hour. 



M. Portier points out that larvso of Gastrophilus have only been found in 

 just those very animals in which a gall-bladder is wanting, namely, the 

 Equjdj::, the elephant and the rhinoceros ; but, as a matter of fact, this is by 

 no means a complete list of the mammals in which there is no gall-bladder. 

 The author argues that this correlation cannot be regarded as a simple 

 coincidence, and suggests that in animals having a gall-bladder the bile 

 may regularly regurgitate into the stomach and so destroy any larvae. He 

 also suggests that ruminants are protected by the fact that the bots can only 

 permanently establish themselves in an acid medium ; in a neutral or alkaline 

 medium they are raj)idly attacked by parasitic organisms. 



