$02 TEXT-BOOK OF PHYSIOLOGY 



tion of even greater significance or else its removal would not be attended 

 with fatal results. 



The Effects of Pathologic Conditions. In recent years the idea has 

 gradually developed that certain pathologic states of the body are associated in 

 some way with pathologic states of the pituitary body. Thus the condition 

 of giantism which begins in youth and the condition of acromegaly which 

 appears in adult life are believed to be the result of a hypersecretion of 

 the anterior lobe, which in turn may be due to a hyperplasia of the gland 

 elements excited by a variety of causes. In both giantism and acromegaly 

 there is an increased activity in the nutritive process leading to an over- 

 growth of osseous tissue and the overlying structures. In the former con- 

 dition the overgrowth is general; in the latter it is confined to the face and 

 the extremities, hands and feet. To this phase of pituitary activity the term 

 hyperpituitarism has been given. 



The opposite condition, infantilism and adiposity, have also been shown 

 to be associated with pathologic changes in the pituitary. In these cases 

 not only is the individual of small size but the genital organs are undeveloped. 

 In addition there may be a subnormal temperature, loss of hair, etc. These 

 phenomena may be due to a diminished or defective secretion partly of the 

 anterior lobe and partly of the posterior lobe. To this condition the term 

 hypopituitarism has been given. 



Goetsch has reported recently that the feeding of an extract of the anterior 

 lobe to young rats "has a stimulating effect upon the growth of the animal 

 and upon its sexual development and activity." Infantilism and a want of 

 sexual development may therefore be due to a deficiency of the anterior-lobe 

 secretion early in life. 



The Effects of Removal of the Posterior Lobe. Gushing in a series 

 of experiments (1911) has demonstrated that the posterior lobe with its epi- 

 thelial investment exerts, contrary to general opinion, a profound influence 

 on metabolism and more especially on the metabolism of the carbohydrates, 

 either alone or in conjunction with other glands having internal secretions. 

 These experiments also led to the belief that some of the phenomena detailed 

 in the foregoing paragraph, especially the deposition of fat, the subnormal 

 temperature and perhaps the imperfect development of the sexual organs are 

 due rather to a deficiency or absence of the secretion of the posterior lobe 

 than to a deficiency or absence of the secretion of the anterior lobe. 



It has apparently been demonstrated by Gushing that the hyaline bodies 

 found in the posterior lobe represent an internal secretion; that they are 

 discharged into the cavity of the third ventricle where they undergo solution 

 in the cerebrospinal fluid, by means of which the dissolved material 

 enters the blood-stream, since compression of the infundibular stalk gives 

 rise to an accumulation of the hyaline material. The presence in the cerebro- 

 spinal fluid of an agent that produces the same physiologic effects when 

 intravenously injected, as injections of extracts of the posterior lobe do, has 

 also been established. 



In the various operative procedures incident to the removal of the entire 

 hypophysis or of the anterior lobe a transient glycosuria is frequently ob- 

 served, a phenomenon attributed to the discharge under the circumstances of 

 an excessively large amount of the reserve hyaline substance or of the 

 posterior lobe secretion into the cerebrospinal fluid in the third ventricle. 



