OCR Text |
Show 1874.] VOMITED BY HORNB1LLS. 423 families of birds (strato epiteliale, Molin) is composed of a corneous, and, in thin slices, pale yellow transparent substance. The lower surface of this lies upon the subjacent follicular layer (Flower), the former dovetailing with the papillae of the latter. As the horny layer ascends it exhibits a series of vertical, parallel, and cylindrical columns, each homogeneous in composition and with intervening epithelio-granular substance. Towards the free surface the columnar character ceases, and is replaced by loosely arranged epithelium-scales. In some genera of birds the columns are found to be tolerably regular and equidistant; in others they are more unequally distributed or form aggregated groups. A portion, though, I find, (not the whole) of the large sac obtained from the Subcylindrical Hornbill corresponds in its minute structure with the above description in every particular. In the vertical section (A, fig. 2, p. 424), and more highly magnified portion of the same (B), short tubular prolongations are observed inferiorly. These, in some instances, have a compound character terminally, while optically deeper or beyond them others similar in kind are visible. By different focusing of the object, a granular and partly fibro-cellular thin connective layer is seen, moreover, to invest the tubes just above their free ends. This produces an appearance suggestive of the lower extremities, seeming tubules, being short, compound, granular flasks, which decidedly they are not, but only the unequal extension of the homogenous pillars above mentioned. These latter, in this perpendicular view, are long rods barely to be distinguished from the intermediate substance, on account of the latter being less transparent. At different levels, more defined indications of horizontal stratification or lamellar layers obtain. At the top of the rods there is a copious development of large nucleated and granular columnar epithelium. Here and there also some of the tubules have been squeezed out, and, along with the narrow ends of epithelial scales, present an irregular fringed margin. In the horizontal sections of the same object (C, D, E ) , the solid nature of the rods is manifest, and it becomes abundantly evident that several rods (averaging 4 to 5) lying in apposition constitute a column or cylindrical bundle. These latter are dispersed at tolerably equidistance, though not precisely regular in contour or calibre ; and this causes a grade or variety in the pattern. From the difficulty of cutting a perfectly flat, uniform section, a partly tangental one occasionally results; but this more clearly shadows forth the coalescence of the homogeneous rods, and how their aggregation into pillars is effected. At other places it likewise admits of the molecules and nucleolar-celled character of the intercolumnar tissue being studied. With regard to the other smaller sac, I have not been fortunate in m y search to obtain tissue answering to the above cylindroid character, but find it simpler or less differentiated in its elements, agree-larged vertical section through all the coats of the stomach of the Heron, which well enables the relations of the strata to one another to be studied. Klein, in his articles "Oesophagus"and "Stomach" in Strieker's'Manual,' pp. 536 & 554. |