Chap. 15 



CHEMICAL REGULATION ENDOCRINE GLANDS 



263 



Fig. 15.7. A "thyroid dwarf"; childhood myxedema. "The Court Dwarf of Don 

 Balthazar Carlos" painted by Velasquez, 1631. The dwarf has the characteristic 

 "saddle nose" and pudgy face and body of thyroid dwarfs. (Courtesy, Boston 

 Museum of Fine Arts.) 



with iodine or keeping them in dilute solutions of iodine also hastens metamor- 

 phosis. 



The skin of human cretins is thickened and dry. If the thyroids are removed 

 from newts {Triturus viridescens) their skin likewise becomes thickened and 

 dry (Fig. 15.9). Newts normally shed their skins at intervals but after their 

 thyroids are removed they cease molting and accumulated layers of skin cover 

 the body or hang from it in tatters. The same effect occurs after the pituitary 

 is removed because the pars anterior controls the activity of the thyroid. 



Parathyroid Glands 



The first important discovery regarding the parathyroid glands was the 

 distinction between them and the thyroid glands on the dorsal side of which 

 they are embedded (Fig. 15.1). In the earlier treatment of goiter the para- 



