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Show 422 DR. J. M U R I E O N T H E SACS [June 16, the Hornbill group, the undermentioned instance (occurring in an African species now alive in the Gardens) substantiating such a view. The accompanying woodcut (fig. 1, A ) illustrates the exterior appearance of one of the objects in question. Its history is as follows : - " This case was thrown up by the Subcylindrical Hornbill (Buceros subcylindricus, Sclater), August 5th, 1872. The bird had commenced to peck it to pieces and eat the fruit it contained at the time it was thrown up. The keeper caught the bird (a male) in the act of eating it." The drawing (fig. 1, B ) represents another of the sacs, which, as I was informed, came from the same bird, but was cast up at a later date, the precise date not being noted. Both retain, pretty correctly, the rugose character observable when freshly expelled, although they were kept in spirits prior to being sketched. That lettered A is much larger than B, on account of the contained food having been removed and cotton in sufficient quantity replaced, so as to prevent undue shrinkage. It is therefore of tolerably natural dimensions. The fruit enclosed within B was left in place ; but it, as well as the wall-membrane, had contracted very considerably from its original size. The contrast between the two is instructive as showing behaviour virtually the counterpart of the corneous gastric texture; and this similarity of tissue is confirmed when a portion is dried, it then becoming translucent and brittle. It would be superfluous for me to say more concerning the external aspect and contents of these figured sacs, other than that they agree in every particular with Mr. Bartlett's, Professor Flower's, and m y own descriptions already published-with the exception that the smaller one contained, in addition, a gooseberry. Their intimate microscopic texture is of more consequence, and, as I apprehend, affords a clue to the solution of the problem. For this reason I have been particular in making accurate sketches under different magnifying-powers. I may premise by stating that certain portions of the tissue of the two sacs differ in one essential particular, this very discrepancy, however, elucidating and tiding over a difficulty. In brief, it most conclusively demonstrates that the constituents, at this part at least, can be no other than the entire thickness of the horny layer of the gizzard. According to the researches of Molin*, Flowery, Hasselj., and others §, the inner coat of the gizzard in various orders and * " Sugli stomachi degli uccelli," in Denkshr. d. Acad, zu Wien, 1852, vol. iii. pt. 2, p. 1, tab. i.-iv. A well-illustrated investigation. t " O n the structure of the Gizzard of the Nicobar Pigeon and other Grani-vorous Birds," P. Z. S. 1860, p. 330, pis. 175,176. Substantiates the conclusions of the foregoing author. \ " Beitrage zur Histologie des Vogelmagens," Zeitsch. f. ration. Med. vol. xxviii. p. 1. As bearing on the question of bird-secretions, see also his paper, "Ueber den Oesophagus der Tauben, &c," Henle and Pfeuffer's Zeitsch. vol. xxiii. p. 101. Also Bergmann " Einiges iiber den Driisenmagen der Vogel," Eeich. & D. B. Eeymond's Archiv, 1862, p. 581. § Berlin, in Ned. Lane. July and Aug. 1852, quoted by Kolliker; but the original article I have not seen. Leydig, in his ' Histologie,' p. 309, gives an en- |