GROWTH AND STRTTCTURE OF HYPOPHYSIS IN RAT 



333 



months. In these cases, although the body weights and hy- 

 pophysis weights are nearly normal, the lobes are abnormal in 

 their relative size. In each the pars anterior is relatively small, 

 and the pars nervosa large. This resembles the change found 

 after mamtenance in young rats and chronic inanition in older 

 rats. It is therefore probably a persistent effect of the inanition 

 during the prolonged jieriod of maintenance. 



VOLUMETRIC ANALYSIS OF TISSUES AND CELLS IN PARS ANTERIOR 



As shown in table 3, data were obtained in eight cases by the 

 method previously described. A larger number of observations 



TABLE 3 



Volumetric data on the component parts {tissues and cells) in the pars anterior 

 (distalis) of the hypophysis of the albino rat under various conditions. 



would doubtless reveal much individual variation, so that no 

 great emphasis can be laid upon the exact figures in the data 

 obtained. These quantitative data confirm the general impres- 

 sions noted in the much larger nmnber of cases studied, however, 

 so that the gener!al conclusions may be regarded as fairly certain. 



a. Relative volumes of stroma and parenchyma {table 3) 



In the pars anterior of the normal newborn, rat, the vessels 

 and associated stroma form 6.7 per cent of the total volume, 

 increasing to 9.6 per cent at three weeks and to 10.6 per cent at 



