The American journal of anatomy . and nuclei, however, it was found that the results, though oflimited value, could not be obtained with sufficient accuracy tojustify any \ery extensive series of obser\ations. Therefore thenumber of measurements was restricted to that judged sufficientto give merely an approximation of the apparent average andrange obser\e{l. Till-; rii\ i;()ii) (;) The normal structure of the thyroid gland in the albino ratat various ages will first be considered. Then the changes foundin the various types of inanition will be described and their sig-nificance discussed.
The American journal of anatomy . and nuclei, however, it was found that the results, though oflimited value, could not be obtained with sufficient accuracy tojustify any \ery extensive series of obser\ations. Therefore thenumber of measurements was restricted to that judged sufficientto give merely an approximation of the apparent average andrange obser\e{l. Till-; rii\ i;()ii) (;) The normal structure of the thyroid gland in the albino ratat various ages will first be considered. Then the changes foundin the various types of inanition will be described and their sig-nificance discussed. 308 C. M. JACKSON a. Norinal structure of the thyroid gtand The general form and topography of the thyroid gland in thealbino rat is shown in cross section in figure 1. Each laterallobe presents the typical relations—convex external surface cov-ered by the infrahyoid musculature; conca^e internal surface incontact with the lower larynx and upper trachea; and narrowerposterior surface (or border) in relation with the oesophagus. Fig. 1 From a photograph (retouched^ of a cross set-tiou of the thj-roid glandin situ at the level of the isthmus, showing relations to infrahyoid musculature,uppermost trachea, oesophagus, etc. One parathyroid is visible, on the left sideof the figure. From albino rat No. S , age 22 days, gross grams. (X 28.) medially the carotid artery, etc., laterally. The isthmus is fre-quently a very thin somewhat fibrous band, almost invisiblewhen the fresh gland is exposed in situ. It invariably containsthyroid follicles (contrary to Sobotta 15), although these maybecome scattered and more or less atrophied in adult rats. The minute structure of the normal thyroid gland at 3 weeks(the age when the experiments began with the younger rats) isshown with slight magnification in figure 1, and under high powerin figure 2. No attempt will l)e made to describe in detail the INANITION OF THYIiOII) IN RATS 309 minute structure of the gland, but some o
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Keywords: ., bookauthorwi, bookcentury1900, bookdecade1910, booksubjectanatomy
