The American Anatomical Memoirs Volume 11 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...amply sustained. The growth curves of the albinous frog tadpoles supplied with either alcoholic or aqueous residues show the same maintenance of growth as is exhibited by their fellows fed with the fresh anterior lobe (figs. 3, 4). No 'critical point' appears; the three curves are coincident. This is not the case with frog albinos receiving aqueous extract, Tethelin, or colloid (figs. 3, 4, 5). Their curves are quite similar to that of the liver-fed albinous larvae. The same early retardation is noted, the 'critical point' is well marked, but appears at a somewhat earlier period (twelve days) and at a somewhat smaller average stage (6 mm.) than their liver-fed companions. Following the critical point, some divergence appears in the three curves. The specimens supplied with aqueous extract exhibit a slight secondary acceleration in growth, but they do not attain quite the average length of their liver-fed mates. The 'Tethelin' group does not exhibit any secondary acceleration subsequent to the 'critical point, ' while the colloid group exhibits an even greater retardation than its fellows supplied with Tethelin. In order to further test the growth effects of hypophysectomy and its response to an anterior-lobe diet, a series of experiments similar in every way to those just reported upon were carried out with toad larvae. These larvae respond in general in the same way as the similarly treated frog tadpoles. The early retardation, the usual midlarval slowing ('critical point'), followed by slow growth, appears as in the frog tadpole (fig. 6). In this, my observations are somewhat at variance with those of Allen, who reports no retardation in the velocity of growth in hypophysectomized toads. Fuller reports may explain this essential difference in our results. ..