EFFEC^TS OF INANITION UPON THE STRUC'TURE 



OF THE THYROID AND P.ARATHYROID 



GLANDS OF THE ALBINO RAT 



C. .M. JACKSON 



hisliUtle of AndloiNji, University of Minnesola, M inrieapolis 



FOURTEE.V FIGURES 



CONTENTS 



Introdiiotion 305 



Material and methods 306 



The thyroid gland 307 



a. Normal structure of the thyroid glanfl 308 



b. Structure in young rats held at maintenance 315 



c. Structure in adult rats after acute and chronic inanition 322 



d. Discussion and conclusions 324 



The parathyroid gland .• 335 



a. Normal structure of the parathyroid 335 



b. Structure in young rats held at maintenance 342 



c. Structure in adult rats after acute and chronic inanition 344 



d. Discussion and conclusions 345 



Summary 348 



Literature cited 350 



INTRODUCTION 



The thyroid gland presents an interesting and difficult bio- 

 logical problem. Although the morphology of the thyroid has 

 been extensively studied, there are still many doubtful and un- 

 settled questions concerning its development and its normal adult 

 structure. Even more uncertainty exists concerning its physio- 

 logical significance and its pathological changes. Some light 

 may be throw^i upon the various phases of this problem by a 

 study of the changes produced in the thyroid gland by inanition. 



In previous papers f Jackson '15 a, '15 b) it was shown that 

 during inanition the various organs of the albino rat suffer very 

 unequally in loss of weight, the loss also varying according to 



305 



