764 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



into the third ventricle of the brain. These hyaline globules are greatly 

 increased after thyroidectomy. It should be mentioned, finally, that at 

 the margin of the intraglandular cleft the intermediary and anterior 

 portions of the pituitary come together, although the cells of each can 

 readily be distinguished on account of their staining properties. This 

 pars glandularis et intermedia also extends as a thin layer over part of 

 the pars nervosa and around the neck of the gland at the infundibulum. 

 These relationships are well shown in the accompanying diagram (Fig. 

 196). 



Functions 



Concerning the functions of the pituitary, it may be said in general that 

 the anterior lobe has an important relationship to the nutritive con- 

 dition of the body during growth, especially of the skeletal structures, 

 and that the posterior lobe produces a very active autacoid having to do 

 with the physiological activity of unstriped muscle fiber. The pars inter- 

 media seems to be associated with the posterior lobe in the production of 

 this autacoid. The function of these two parts will therefore be con- 

 sidered together. 



Function of the Anterior Lobe. The facts concerning the function 

 of the pars glandularis have been gleaned largely by observing the ef- 

 fects produced by partial or complete removal of the entire pituitary, 

 justification for ascribing to the removal of the anterior, rather than 

 the posterior, lobe the results that are obtained being furnished by control 

 experiments, in which by removal of the posterior lobe alone similar 

 effects are not observed. 



Complete removal of the pituitary is almost invariably fatal, the con- 

 dition being called apituitarism. Two operative procedures have been 

 employed for the removal of the gland. One of these, elaborated by Gushing 

 and his pupils, 82 consists in trephining the skull and elevating the temporal 

 lobe of the cerebrum so as to expose the gland. The other, elaborated 

 by Horsley, 83 consists in approaching the gland through the orbital 

 cavity. Although there is some danger of injury to nervous tissues by 

 the intracranial method, its results are more dependable since the gland 

 is actually exposed to view before being removed. 



Most hypophysectomized animals die within two or three days, unless 

 they are very young. This longer survival of young animals is ascribed 

 to the presence of accessory pituitary material situated in the dura mater 

 lining the sella turcica. The most extensive observations have been made 

 on dogs. On the day following the operation the animal appears about 

 normal, but it gradually becomes less active, refusing food and respond- 

 ing slowly to stimulation. It gradually gets weaker and weaker; muscu- 



