452 INANITION AND MALNUTRITION 



to 10.6 per cent at ten weeks (adult condition). In young animals held at main- 

 tenance, the volume of the vascular stroma usually increases to about 13 per 

 cent, and in acute or chronic inanition of adults to about 17 per cent. The 

 parenchyma is, of course, correspondingly reduced in relative volume. 



"In the parenchyma of the pars anterior the nuclei form about 34 per cent 

 of the total cell volume in the newborn, decreasing to about 24 per cent at three 

 weeks and to 20 per cent at ten weeks (adult relation) . The cytoplasm increases 

 correspondingly in relative volume. During inanition, the loss is usually 

 greater in the cytoplasm, the nuclei thereby increasing to 26-28 per cent of the 

 cell volume in the young held at maintenance, and to 23-26 per cent in adults 

 with chronic or acute inanition. 



"According to data obtained by the volumetric method, the (calculated) 

 average diameter of the parenchyma cells of the anterior lobe increases from 

 8.4M in the normal newborn to 9.3^ at three weeks and 10.4/x. at ten weeks (adult 

 condition). In young rats held at maintenance, the average cell diameter is 

 reduced to 7.8-8.1/x; in starved adults to 8.6-8.7,11. (Note. These corrected 

 diameters are slightly smaller than the erroneous data in the original paper.) 

 The nuclear diameter averages 5.9/i in the normal newborn, 5.8/x at three weeks, 

 and 6.0ju at ten weeks. In the young rats at maintenance the nuclear diameter 

 is reduced to 4.9-5.3/1; in starved adults to 5.3-5.5/*. Direct measurements 

 by another method (with filar micrometer) gave similar results for the nuclear 

 diameters, including also those of the pars intermedia. 



"The number of mitoses in an entire section of the gland is quite variable. 

 Amitosis was never observed. In the normal newborn pars nervosa, the average 

 number of mitoses is 7 per section; at seven days they are rare, and none occur 

 later. In the pars intermedia, the average number decreases from 9 per section 

 in the newborn to about 1 at three weeks; at ten weeks and later they are rare. 

 In the normal pars anterior the rate likewise decreases, being about 62 at birth, 

 18 at one week, 7 at three weeks, 2 at ten weeks and rare in adults. 



"In young rats held at maintenance from three to ten weeks of age, mitosis 

 has nearly ceased. No mitoses were found in the partes nervosa and intermedia, 

 although in the pars anterior they still occur occasionally, even in rats nearly 

 dead from inanition. No mitoses were observed in the starved adults. 



"In the young rats refed after the maintenance period, mitoses reappear 

 promptly in the pars anterior, the average number per section being about 

 2 after one-half week of refeeding, 7 after one week to two weeks, decreas- 

 ing to an average of 3 after four weeks of refeeding. Mitoses were observed but 

 rarely in the pars intermedia, and never in the pars nervosa. The rate of 

 mitosis in the hypophysis of the refed rats therefore corresponds roughly to 

 that in younger normal rats of similar body weight. 



"In cell structure, the only change noted in the pars nervosa during inanition 

 is a variable degree of hyperchromatism in the nuclei, which rarely may become 

 shrunken and pycnotic. In the pars intermedia, most of the cells usually suffer 

 relatively little change during inanition. The nuclei have a variable tendency 

 to hyperchromatism, occasionally becoming pycnotic, especially in certain 

 atrophic areas. The cytoplasm tends to lose its granular structure, becoming 



