THE DUCTLESS GLANDS 



1243 



anterior lobe. The cells, which present but few granules, are arranged in islets, separated 

 by an intervening tissue continuous with the main mass of the posterior lobe. Many 

 of the islets are hollow and enclose a colloid material. The colloid material has been 

 traced by Herring into the interalveolar connective tissue and into the prolongation 

 of the infundibulum which enters the posterior lobe. One must therefore conclude that 

 the colloid material secreted by the cells of this part passes directly into the third 

 ventricle. The amount of colloid material increases in animals which have undergone 

 extirpation of the thyroid gland. 



Our first clue to the importance of this organ in the normal processes 

 of the body was furnished by the observations of Pierre Marie, who found 



FIG. 563. Section of cat's pituitary body, passing through the cleft in the gland. 



(P. T. HERRING.) 

 a, pars anterior ; b, cleft ; c, pars intermedia ; d, pars nervosa (posterior lobe). 



that the morbid condition of acromegaly is associated with tumours of the 

 pituitary gland. This disease consists in an increased growth of certain 

 parts of the skeleton, especially the lower jaw and the extremities of the 

 limbs. Headache is often present, and there may be polyuria and affection 

 of the eyesight. When this disease occurs during the period of active growth, 

 there may be an increase in length both of the limb-bones and of the trunk, 

 and most of the giants, which are shown from time to time, are examples of 

 this pathological condition of ' gigantism.' It seems probable that this 

 condition is due to an over-action of the gland. In cases of acromegaly the 

 tumour is generally an adenoma, i.e. an. enlargement of the ordinary gland 

 tissue. It has not been possible by transplantation to replace a removed 

 pituitary body, since the transplanted organ has hitherto always undergone 



