140 



C. M. JACKSON 



there is a decided decrease in the weight of the hver. Thus the 

 Hver would appear under these conditions to have a tendency to 

 follow the normal growth-impulse, which increases to a maximum 

 at about the age of six weeks, and decreases thereafter (Jackson 

 '13, p. 31).. 



During inanition in adult rats, the liver loses in weight rela- 

 tively more than the whole body, and to a greater extent in acute 

 than in chronic inanition (Jackson '15 c). As the liver is nor- 

 mally subject to great variation in weight, however, (Jackson '13) 

 great caution must be observed in drawing final conclusions. 

 Hatai ('13) found the weight of the normal liver distinctly higher 

 than that in my series, and if his data instead of my controls 

 were taken as a basis for the ini^tial weights, the estimated losses 

 in my experiments would be considerably greater, even the 

 younger rats showing a loss instead of a gain in liver-weight. 



SPLEEN 



Taking the controls at three weeks as a basis for com- 

 parison, it appears that in rats held at constant body-weight 

 from the age of three weeks to six weeks the weight of the spleen 

 (table 18) remains practically unchanged (the average at six 



TABLE 18 



The spleen; average absolute weight, average percentage of net body-weight and range 



indicated 



DESCRIPTION OF RATS 



Normal at 3 weeks (Jackson '13) 



Controls at 3 weeks 



Body-weight constant 3 weeks (age ot 3 to 6 weeks) 

 Body-weight constant 5 weeks (age of 3 to 8 weeks) 

 Body-weight constant 7 weeks (age ot 3 to 10 weeks) 



Normal at 6 weeks (Jackson '13) 



Control at 6 weeks 



Body-weight constant 26 weeks (age of 6 to 32 weeks) 



Normal at 10 weeks (Jackson '13) 



Controls at 10 weeks 



Body-weight constant 25 weeks(age ot 10 to 35 weeks) 

 Controls at 32 and 35 5\'eeks 



absolute weight 

 (and r.\nge): grams 



0.055 (0 

 0.091 (0 

 0.087 (0 

 0.043 (0 

 053 (0 

 0.135 (0 

 0.107 

 0.139 

 0.225 

 0.350 (0 

 0.230 (0 

 0.620 (0 



019-0.145) 

 051-0.130) 

 040-0.172) 

 036-0.049) 

 033-0.076) 

 086-0.204) 



300-0.420; 

 230-0.240) 

 480-0.750) 



relative weight 

 (and range): 



PER CENT 



0.28 (0, 

 0.37 (0. 

 0.38 (0 

 0.24 fO. 

 0.22 (0 

 0.28 (0 

 0.25 

 0.29 (0. 

 0.30 

 0.27 (0 

 0.30 (0 

 0.33 (0 



15-0.42) 

 27-0.48) 

 18-0.72) 

 20-0.27) 

 16-0.33) 

 19-0.47) 



28-0 30) 



21-0.36) 

 2V-0.33) 

 29-0.39) 



