142 



CM. JACKSON 



increase of about 28 per cent. Between six and tiiirty-two 

 weeks there is apparently but little change; while from ten to 

 thirty-five weeks there appears to be a decrease in the weight of 

 the alimentary canal. The number of observations, however, 

 is too small for final conclusion. 



The most remarkable increase occurs between three and six 

 weeks of age, from an absolute weight of 1.20 to 1.78 grams, an 

 apparent increase of about 48 per cent in absolute weight! (The 

 increase would be even greater if allowance were made for differ- 

 ence in body-weight). Thus, as in the case of the liver and 



TABLE 19 



The stomach and intestines; average absolute weight, average percentage of net body- 

 weight and range indicated 



DESCRIPTION OF RATS 



a. Including contents 



Normal at 3 weeks (Jackson '13) 



Controls at 3 weeks 



Body-weight constant 3 weeks (age of 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) 



Controls 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 of 10to35 weeks) 

 Controls at 32 and 35 weeks 



h. Empty 



Normal at 3 weeks (Jackson '13) 



Controls at 3 weeks 



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

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

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



Normal at 6 weeks (Jackson '13) 



Controls 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 of 10 to 25 weeks) 

 Controls at 32 and 35 weeks 



.ABSOLUTE WEIGHT 

 (.\ND R.VXGE) : GRAMS 



1.78 (0.74-3.08) 

 2.51 (1.96-3.23) 

 3.10 (1.67-5.07) 

 3.64 (2.58-4.71) 

 3.29 (2.26-6.83) 

 8.05 (4.48-13.40) 

 5.13 



5.98 (4.71-7,24) 

 9.00 



11.32 (8.82-14.49) 

 7.48 (5.90-8.81) 



11.60 (7.51-14.04) 



0.90 (0.37-1.61) 

 1.20 (0.74-1.69) 

 1.78 (1.41-2.51) 



1.44 (1.38-1.51) 



1.45 (0.96-2.29) 

 4.00 



3.00 



3.22 (2.85-3.59) 



5.30 



5.26 



3.97 (3.48-4.35) 



9.16 (7.57-10.64) 



relative weight 

 (and range): 



PER CENT 



9,3 ( 5.5-15.5) 



10.4 (7.8-15.4) 

 13.9 (7.4-21.3) 

 20.2 (4.5-26.0) 



13.5 (10.3-20.2) 

 15.9 (10.6-23.4) 

 12.1 



12.5 (10.8-14.2) 

 12.0 



8.3 ( 7.3-11.2) 

 9.6 ( 8.1-10.4) 



7.4 ( 5.4-12.2) 



4.5 ( 2.9- 6.1) 

 4.8 ( 3.1- 6.7) 

 8.0 ( 6.3-U.O) 

 8.0 ( 7.8- 8.3) 

 6.0 ( 4.5- 8.6) 

 8.0 

 7.1 



6.8 ( 6.5- 7.0) 

 7.0 



4.3 ( 3.9- 4.9) 



5.4 ( 4.7- 5.9) 



4.9 ( 4.1- 5.3) 



Body-weight of controls at 10 weeks too great for comparison with those held constant 10-35 weeks. 



