186 



NORMAL HISTOLOGY. 



into thyroid tissue when the gland furnishes an insufficient supply of 

 secretion. Other observers deny this and regard the parathyroids 

 as embryonic rudiments, nearly, if not quite, devoid of function. It 

 is certain that in some cases of thyroidectomy the parathyroids 

 become enlarged, and that the cachexia strumipriva is not certain to 

 develop after the removal of the thyroid gland unless the parathy- 



FIG. 161. 



-n 



Section of the inner parathyroid of a kitten two months old. (Kohn.) Showing its close 

 connection with the tissues of the thyroid gland : Sch, alveoli of the thyroid ; P, epithelial 

 columns of the parathyroid ; K, capsule separating the two. 



roids are also removed. Histological studies of the parathyroids in 

 such cases have, however, failed to reveal a tendency on their part 

 to develop into true thyroid tissue. Their relations to the thyroid, 

 therefore, still remain undetermined. 



In some animals e. g., the cat there are four parathyroid bodies, 

 two associated with each lobe of the thyroid. 



3. The Adrenal Bodies (Fig. 162). The adrenal bodies, or supra- 

 renal capsules, possess a fibrous capsule, which is more areolar 

 externally, where it frequently merges into the perinephric fat, 



