446 



MAMMALIA— PHYSIOLOGY 



hypertrophy. Possibly disturbance of the calcium-iodin balance 

 will also account for non-bacterial cases due to water. 



The writer cannot resist the opportunity to again pay tribute to 

 McCarrison for his initial discovery of the significance of the iodin- 

 fat balance and to deplore the fact that it is now receiving such 

 belated recognition, more than twelve years after its discovery, 

 in 1919. 



Internal Jugular vein j-r^K " 



Middle thyroid vein — 

 Inferior thyroid vein-—. 



Thyroid 



— Common carotid 



Median furrovi/ 

 of thymus 



Lun^- 



FiG. 243. The thyroid and thymus in a child of six months. (Sappey.) (Schafer's 

 Text Book of Mic. Anat. Courtesy of Longmans, Green & Co., London.) 



Parathyroids. — The parathyroids have been operatively removed 

 with the thyroids, and death ensued, after a condition of tetany. 

 The parathyroids influence calcium metabolism, and also affect 

 sugar metabolism, and aid in preserving the nitrogen balance. 



Thymus. — The thymus gland degenerates at puberty, and may 

 be concerned with both the thyroids and the gonads. Soli, and 

 later. Riddle, believed that the thymus was concerned with calcium 



