STUDIES OX THE EXDOCRIXE GLAXDS:-IV.: THE EFFECTS 

 IN THE DOG UPOX THE KEMAIXDER OF THE THY- 

 ROID AXD PARATHYROID OF PARTIAL REMOVAL OF 

 THOSE ORGAXS. By Masaharu Kojima, Fleet Surgeon, Imperial 

 Japanese Navy. (From the Physiology Department of Edinburgh 

 University.) (With two figures in the text.) 



{Received for publication 1st December 1916.) 

 CONTENTS. 



I'AISK 



Structure op the Thyroid and Parathyroid of the Doo . 347 



Operative Procedures and their Effects ..... 348 



Summary .......... 349 



Structure of the Thyroid and Parathyroid of the Dog. 



Before describing the results of operations upon the thyroid and para- 

 thyroid, the chief points regarding the microscopical structure of these 

 glands in the normal animal may be enumerated. 



The Thyroid (fig. 1). — The vesicles vary in size and shape : they are 

 lined by distinctly cubical epithelium. The cytoplasm of the cells is finely 

 granular, and stains faintly with eosin. The cell-nuclei are round or slightly 

 elongated, and of nearly equal size (5/>i). They contain fine chromatin 

 granules, and most of them are deeply stained by hematoxylin. Between 

 the vesicles is the connective tissue accompanied by blood-vessels. The 

 vesicles are filled with a colloid which, in hsematoxylin-eosin preparations, 

 is stained of a faint red colour, with a nuance of purple. Between the 

 vesicles are groups of epithelium cells ; possibly some of these are due to 

 walls of ve.sicles cut tangentially. 



The Parathyroids. — These are both internal and external. In 

 number and position they show many departures from the type 

 (M'Callum and others). The internal are embedded in the thyroid 

 substance, lying either in the upper or middle third of each lateral lobe. 

 Both the internal and external parathyroids have a compact appearance, 

 consisting of small epithelium-like cells. Their nuclei are about 5/x in 

 diameter, and contain fine granules of chromatin. The blood-vessels are 

 convoluted. Xo vesicular arrangement of the cells is apparent. A thin 

 capsule of connective tissue surrounds each parathyroid and separates the 

 internal parathyroid from the thyroid substance. 



