PROPORTIONS OF THE TECTORIAL MEMBRANE 11 



after death shows beginning maceration or digestion of the organ 

 to an extent usually rendering it very unsatisfactory. Pig 

 embryos and fetuses kept in the uterus and therefore in the am- 

 niotic fluid, preserve somewhat longer, but in the older stages 

 of these digestion of the elements of the organ begins remarkably 

 quickly. Therefore, it was found very necessar^^ to place the 

 cochleae in the fixing fluid, directly from the freshly killed 

 animals. 



The human specimens were obtained at autopsy but were 

 found even in the freshest case to which access could be obtained, 

 to have suffered too much dissolution for trustworthy detailed 

 study of either tectorial membrane or spiral organ. All the 

 pig material and the cochleae of the ox were obtained and placed 

 in fixing fluid at the slaughter-house. Fortunately, , in the 

 slaughter-houses of New Orleans, the hog is always split sagit- 

 tally along the vertebral column and through the head immedi- 

 ately after evisceration. One has but to stand near the line of 

 the passing carcasses, beyond the man who removes the brains, 

 likewise split, and an abundant supply of adult labyrinths may 

 be obtained from them within a few minutes after death. The 

 bony labyrinth of the pig does not become fused to nor embedded 

 in the petrous portion of the temporal bone as it is in man. In 

 the pig fetus, it may be 'shelled out' with the fingers. In the 

 adult hog it has developed considerably more bone than in the 

 fetus, some of which excess is in the form of flattened bony proc- 

 esses extending adjacent to and parallel with the cranial sur- 

 face of the temporal bone. The most evident of these proc- 

 esses extend from the region of the semicircular canals and, 

 after pulling away the dura mater that may be left, a sharp 

 screw-driver may be inserted under these processes, given a 

 twist and the entire bone labyrinth is readily removed. The 

 mesial surface of the bony labyrinth of the ox is likewise visible 

 in the cranial wall but is more firmly planted in the temporal 

 bone, though not wholly fused to it. Its removal requires a 

 stronger screw-driver and greater effort, or even a chisel and 

 mallet. 



