CALCIFEROUS GLANDS 35 



Various theories as to the significance of these glands have been 

 put forward from time to time. It now seems reasonably settled 

 that these glands are organs controlling the acid-base balance of 

 the body. They fix a certain percentage of the metabolic carbon 

 dioxide produced by the body, and this can be changed according 

 to the amount of atmospheric carbon dioxide present. Coelomic 

 pH is maintained at a stable level, but removal of the calciferous 

 glands is followed by an increasing acidity of the coelomic fluid. 

 Carbonic anhydrase, an enzyme concerned in acid-base reactions 

 in other animal tissues, is present in large amounts in the glands. 

 An outline is presented of the mechanisms by which calcium 

 carbonate is secreted by the glands, two processes occurring 

 dependent upon which section of the gland is considered. 



