SECRETION OF THE DUCTLESS GLANDS. 883 



ence upon metabolism, although the nature of this influence is not 

 as yet understood. Removal of the posterior lobe alone is not 

 fatal, but it is followed by characteristic effects. The animal 

 exhibits a greater tolerance to carbohydrate food, that is to say, a 

 larger quantity of carbohydrate can be taken without causing 

 alimentary glycosuria. There is also a marked increase in the 

 processes of fat formation, so that a tendency to obesity is one 

 indication of a diminished activity of the posterior lobe. When the 

 operation is performed upon young animals the development of the 

 sexual glands is arrested, and the animal later exhibits a eunuchoid 

 condition. On the clinical side observations have been collected 

 which corroborate and extend the conclusions that might be drawn 

 from the results of animal experimentation, although in such cases 

 it has been more difficult to separate the effects due to the anterior 

 and the posterior lobes respectively. When the hypophysis is 

 hypertrophied and is presumably in a condition of hyperactivity, 

 the resulting effects are exhibited chiefly in the matter of the 

 growth of the skeleton. In early life such an effect leads to marked 

 overgrowth or gigantism, while in later life it occasions an enlarge- 

 ment of the bones of the face and extremities, a condition known as 

 acromegaly. It is assumed that in such cases there is a hypersecre- 

 tion of the anterior lobe. On the other hand, when there is reason 

 to believe that there is a diminished activity of the pituitary body, 

 for example, from pathological growths pressing upon the gland, 

 the effects usually observed are the production of obesity and sexual 

 infantilism, together with increased tolerance to carbohydrates. 

 These effects are attributed to a hyposecretion of the posterior lobe. 

 The Functions of the Pituitary Body. It seems evident from the 

 above brief statement of the results of experiments and clinical 

 observations that the pituitary body is essential in some way to 

 normal body-metabolism, and moreover that the anterior and pos- 

 terior lobes exercise different functions. The differentiation in 

 function between the two parts or two glands cannot be made 

 completely at present, but so far as our knowledge goes it would 

 seem that the anterior lobe furnishes a secretion that stimulates 

 the growth of the skeleton and possibly the connective tissues in 

 general, and in addition exercises some deeper influence on metabo- 

 lism of an unknown but essential nature. The posterior lobe, on 

 the contrary, furnishes one or several hormones that have a stimu- 

 lating effect upon several processes the tone of plain muscle, the 

 secretory activity of several glands, and the process of glycogeno- 

 lysis. In addition, this portion of the gland shares with others of 

 the ductless glands (thymus, cortex of the adrenal glands) a regu- 

 lating influence upon the normal development of the reproductive 

 organs. Its influence in this respect resembles and may be con- 



