138 Herrino; 



manner, but the occurrence of colloid in the cleft is, in my experience, 

 rare, and where found histologically has been in large, thin-walled cysts 

 belonging to the epithelium of the neck of the posterior lobe.^ 



Connective tissue and lymphatics are found between the cell columns, 

 and the whole structure is closely united to the under surface of the brain, 

 into which blood capillaries freely penetrate. 



The epithelial cells do not show the regular arrangement which is 

 so characteristic of the thyroid vesicles ; the walls are irregular and may 

 be composed of one or several layers of cells. The cells are small and 

 clear ; fine granules may be present m their protoplasm. The colloid 



fi^' 



^A 



f:f/^m. 



>^ 



'^^^^'^ 



Fk;. 8. — ^Mesial sagittal section through tongue-like ]ii'i((~- if (lar,^ mtemiedia 

 and adjacent part of brain and of anterior lobe juoiier >.l an adult cat. 

 (Photograph x 100.) 



o, third ventricle; 6, portion of anterior lamina of neck of posterior lobe; c, tongue-lilte 

 process of pars intermedia, consisting of epithelial cells in form of solid columns and 

 tubules : many of the latter contain colloid ; d, granular cells of anterior lobe proper. 



material varies in amount in different animals ; it does not stain deeply, 

 and has a somewhat different appearance from the colloid met with in 

 the thyroid. Whether it is the same kind of material or not is open to 

 (juestion. Sclinitzler and Ewald (38) state that thyreo-iodine occurs 

 in the pituitary. 



The junction of the intermediate portion with the anterior lobe is 



1 A pituitary body from an apparently healthy female cat, that had had a litter of 

 kittens a short time previously, showed a large mass of colloid substance surrounding the 

 neck of the infundibulum and occupying a large part of the cleft. The material did not 

 lie free in the cleft, but was surrounded by a single layer of flattened epithelium. The 

 cyst was nearly as large as the posterior lobe, and originated from the eijithelium sur- 

 rounding the neck of the infundibulum. The substance in the cyst was not of a 

 homogeneous nature, but consisted of irregular solid masses lying among a clearer material. 



