BEFORE AND AFTER BIRTH. 401 



covered in them. They are the thyreoid, the thymus, 

 and the supra-renal glands.* 



637. The thyreoid gland f is fixed upon the cartilage 

 of the same name belonging to the larynx, has two 

 lobes, is, as it were, lunated, $ and full not only of 

 blood, in which it abounds in the foetus, but of lym- 

 phatic fluid, and becomes, as age advances, gradually 

 less juicy. 



638. The thymus is a white and very tender structure, 

 likewise bilobular, sometimes completely divided into 

 two parts, occasionally containing a remarkable ca- 

 vity, || placed under the superior part of the middle of 

 the sternum, always ascending as far as the neck on 

 each side,** of extremely great proportionate size in 

 the foetus, abounding in a milky fluid, becoming gra- 

 dually absorbed in youth, and frequently disappearing 

 altogether in old age.tt 



* Vide F. Mechcl, Abhandlungen aus der_ menschlichen u. vergleichenden 

 Anatomic. Halle. 1806. 8vo. He makes it probable that these three organs 

 contribute to the chemical functions of the nervous and hepatic systems, and 

 thus diminish the quantity of hydrogen and carbon. 



\ C. Uttini, Tie glandules thyroidece nsit, in the Comment, instituti Bononiens. 

 Vol. vii. p. 15 sq. 



J Haller, Icones Anat. fasc. iii. tab. 3. 



J. Ant. Schmidtmuller, uber die Avxfuhrungsgange der Schilddriise, 

 Landshut 1804. 8vo. 



H Aug. Louis de Hugo, De glandnlis in genere ft speciatim de thymo. 

 Getting. 1746. 4to. fig. 2. 



Morand the younger, Memoir -es de I'Acad. des Sc. de Paris. 1759. 

 tab. 2224. 



Vincent Malacarne, Memorie della Societa Italiana. T. viii, 1799. P. i. 

 page 239 sq. 



Sam. Chr. Lucae, Anatomiscke Untersuchungen der Thymus. Frankfort, 

 1811. 4to. 



** Haller, Icones Anat. 1. c. 



f-t" Hewson, K.rperiienfal rnqtiirifs. P. iii. psssim. 



2D 



