324 ORIGINAL ARTICLES. 



Arteria ALDITORIA INTERNA. 



Perhaps the most important result which I have obtained from 

 a long series of isolated injections, has been yielded by injecting the 

 internal auditory artery in man and other mammals ; but this artery is 

 so very small that it is quite impossible to introduce into it even the 

 smallest injection tube, so that it is necessary to proceed to inject 

 it in another way. 



Place a ligature round the basilar artery, immediately in front 

 of the origin of the internal auditory, just behind which the basilar 

 artery may be easily fitted with an injection tube of tolerable dimen- 

 sions ; the injection being then prevented by the ligature from pene- 

 trating far into the basilar artery, must pass along into the auditory 

 branch with all the requisite force. Next inject, in the same subject, 

 the middle meningeal artery, with a differently coloured injection ; 

 both these injections must be composed of very fine materials. The 

 investigator will now perceive that the labyrinth is supplied by the 

 auditory artery, while the surrounding substance of the petrous bone 

 is supplied by branches of the meningeal. 



I shall not now enter into more details; these I reserve for 

 another occasion ; but, I may state that this independence of the cir- 

 culations of the labyrinth and of the petrous bone, will account for the 

 very interesting observations made by several French surgeons, and 

 proved by many convincing pathological preparations, in my osteolo- 

 gical collection, that a caries tem/porum may corrode away almost the 

 whole of the petrous bone, without destroying the sense of hearing ; 

 and that the cochlea of a human ear, together with the vestibulum, 

 may be exfoliated through a like caries, just as if prepared by the 

 skilled hand of the anatomist, because the two having separate and 

 independent circulations, each may preserve its integrity apart for a 

 long time. 



I have in my possession a very neat looking cochlea, which was 

 taken out, with a forceps, from the external auditory meatus of an 

 otorrhoic patient by a friend of mine, who is Surgeon to a suburban 

 district in Prague. 



