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.ff 



* Vide F. Mechel, Abhand.lu.ngen aus der menschlichen u. vergieichenden 

 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. 



f C. Uttini, De glandulte thyroideie usu, in the Comment, instituti Bononiens, 

 Vol. vii. p. 15 sq. 



X Haller, Jcones Anat. fasc. hi. tab. 3. 



§ J. Ant. Schmidtmiiller, uber die Atisfuhrnngsgange der SchilddrHse. 

 Landshut. 1804. 8vo. 



|| Aug. Louis de Hugo, De glandulis in genere et speeiatim de thy mo. 

 Gotting. 1746. 4to. fig. 2. 



Morand the younger, Mimoires de tAcad. des Sc. de Paris. 1759. 

 tab. 2: —24. 



Vincent Malacarne, Memorie delta Societa Italiana. T. vhi. 1799. P. i. 

 page 239 sq. 



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

 1811. 4to. 



** Haller, Icones Anat. 1. c 



"H" Hewson, Experimental enquiries. P. iii. passim. 



2d 



