44S CHARLES Ii. STOCKABD AND E. M. VICAIU 



dog in respect to this tendency to produce races and indi- 

 viduals of widely different types and sizes, and in man the 

 disturbances of pituitary function are numerous and classical. 

 On these accounts, it is highly desirable to learn the hereditary 

 reactions in arrested, distorted and otherwise abnormal pi- 

 tuitary conditions in a manner similar to that which we have 

 reviewed for the thyroid gland. The inheritance of pituitary 

 modifications is of special importance in connection with the 

 possible correlation of these modifications with thyroid, gon- 

 adal and other endocrinic disturbances. For such studies we 

 again find among the dogs certain breeds in which the pituitary 

 1 (resents a fairly normal histology without symptoms of 

 disfunction, and other breeds in which there is pronounced 

 histopathology accompanied by both structural and functional 

 symptoms commonly interpreted as resulting from pituitary 

 distortions. By crossing breeds which present these appar- 

 ently contrasted symptoms we hoped to gain information not 

 only concerning the inheritance of pituitary abnormality but 

 also information bearing on the correlation between pituitary 

 defects and the physical and functional disturbances com- 

 monly attributed to them. The first such cross to be con- 

 sidered is between two breeds distinctly contrasted in the 

 above respects: the dachshund and the Boston terrier. 



In many cases the dachshund possesses one of the most 

 typically normal pituitary glands to be found among the pure 

 line dogs. Plate 87 shows photomicrographs of longitudinal 

 sections of the pituitary glands from four prize typed dachs- 

 hunds, but one may readily appreciate that all these are not 

 completely normal. Figure 1, however, may be described as 

 a perfectly normal example of the general arrangement and 

 proportions in the dog pituitary. The anterior lobe or oral 

 hypophysis surrounds the pars nervosa which is, in this 

 specimen, relatively large. The saccular diverticulum from 

 the third ventricle extends completely through the infundibu- 

 lar stalk and penetrates the nervosa, with cellular islands 

 and cords passing from the saccular surface into the tissues 



