THE HISTOLOGICAL APPEARANCES OF THE MAMMALIAN 

 PITUITARY BODY. By P. T. Herring. (From the Physiology 

 Department, University of Edinburgli.) 



{Received for jmhlication llth February 1908.) 



Introduction. 



The structure and significance of the pituitary body have long been objects 

 of much speculation. Erroneous conceptions of its structure are responsible 

 for some of the many theories which have been advanced with regard to 

 its functions. The pituitary, indeed, derives its name from the old idea 

 that it was a gland which discharges a secretion — pituita — into the 

 nostrils. 



Rathke (32) discovered the double origin of the pituitary, and on 

 developmental grounds classed it among glands. Other observers looked 

 upon it as part of the brain. Luschka (23) called it a "nerve-gland" 

 in which the two parts are separated from one another by pia mater. 

 Ecker (8), on the other hand, held the view that both portions of the 

 pituitary combine to form a unit of the nature of a " blood-vessel gland." 



Burdach (4), Luschka (23), and Virchow (46) regarded the posterior 

 lobe as the anterior terminal end of the cerebro-spinal canal, a "filum 

 terminale anterius," resembling in structure the filum terminale of the 

 spinal cord. Virchow also compared the anterior lobe to the thyroid 

 gland, and described in it vesicles containing colloid material which show 

 a striking resemblance to the follicles of the thyroid. Rogowitsch (34), 

 H. Stieda (43), Schonemann (39), and others have attached great 

 importance to this resemblance, and ascribe similar functions to the two 

 glands. Removal of the thyroid is, according to their observations, 

 followed by a compensatory hypertrophy of certain parts of the glandular 

 lobe of the pituitary. 



In bS8() Marie drew attention to a relationship between changes in 

 the pituitary and the disease acromegaly or gigantism. Clinical and 

 pathological experiences have led to the theory which as.signs to the 

 pituitary the role of regulating the normal development of the body, more 

 especially of the extremities and bones. The nature of the change that the 

 pituitary undergoes in acromegaly is uncertain, and before any light can 

 be thrown upon its pathology it is necessary that the significance of the 

 various histological elements that constitute the normal pituitary should 



