WEIGHTS OF ORGANS IN UNDERFED YOUNG RATS 



147 



there is an increase from 0.144 gram (0.57 per cent of the body- 

 weight) to 0.193 gram (0.74 per cent of the body), an apparent 

 increase of 34 per cent in the absolute weight. (The average 

 net body-weight was about the same in both cases, 25.0 grams in 

 the controls, and 25.2 grams at ten weeks). 



For the epididymi (table 22 b), the conclusions are even more 

 uncertain; but there appears to be a slight loss in the relative 

 weight of the epididymi in rats held at constant body-weight from 

 the age of three to six and ten weeks. 



For testis and epididymis combined (table 22 a) there appears 

 to be an increase in rats held at constant body-weight, excepting 

 the period from six to thirty-two weeks. 



While no final conclusions can be drawn, the evidence indi- 

 cates that in young rats held at constant body-weight there is 

 an increase in the weight of the testis, but not in the epididymis. 



During inanition in adult rats, the testes and epididymi ap- 

 parently lose weight in about the same proportion as the entire 

 body (Jackson '15 c). 



OVARIES 



In rats held at constant body-weight from three weeks to ten 

 weeks of age, there would appear to be a decrease in the weight 

 of the ovaries (table 23) from 0.0066 gram (0.0068 gram, less 

 correction for difference in bod}^- weight ; or 0.027 per cent of the 



TABLE 23 



The ovaries; average absolute loeight, average ■percentage of net body-weight and range 



indicated 



DESCRIPTION OF RATS 



ABSOLUTE WEIGHT 

 ( AND RANGE) : GRAMS 



relative weight 

 (and range): 



PER CENT 



Normal at 2 weeks (Jackson '13) 



Controls at 3 weeks 



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

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



Normal at 6 weeks (Jackson '13) 



Normal at 10 weeks (Jackson '13) ^ 



Controls at 10 weeks ':'. 



0.0036(0.0015-0.0067) 



0.0068(0.0029-0.0104) 



0.0067(0.0048-0.0084) 



0.0048(0.0030-0.0064) 



0.0106(0.0050-0.028) 



0.0350(0.0100-0.070) 



0.0337(0.0297-0.038) 



0.0220 (0.011-0.039) 

 0.0270 (0.012-0.034) 

 0.0300 (0. 020-0. 03S) 

 0.0210 (0.012-0.028) 

 0.0216 (0.012-0.035) 

 0.0340 (0.013-0.055) 

 0.0290 (0.027-0.033) 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 19, NO. 2, 



