Sheldon's first plate, I may add, when compared with his letter-press on p. 37, appears to show that what he calls 'ampullulae' were really Peyerian glands, and that he had repeatedly seen these glands distended in the way of natural injection with chyle, as it is easy enough to see them distended in an animal, such as a rat, which can be got to feed on fatty food, and can be killed at a proper interval of time afterwards. He appears to have had very serious as well as reasonable doubts as to the existence of any foramen in the apices of these 'ampullulae'; but the authority of Lieberkuhn, whose Dissertatio Anatomica (p. 18) he had himself edited, appears to have weighed with him more than his avTojria. Near, therefore, as Sheldon came to seeing the whole truth, he just failed of
tion of this material into the parieto-splanchnic ganglion of the Lamellibranchiata when thus employed by the skilful Italian anatomist, Poli, and its distributing itself thence into the nerves given off from it by displacement of their granular neurine, seduced him into supposing these structures to constitute a lymphatic system, 'cisternam lacteam et vasoruni lactiferorum surculos.' See Testacea Utriusque Siciliae, torn. i. p. 39, 1791.
