GROWTH AFFECTED BY FEEDING DUCTLESS GLANDS 331 



IJf.- Alimentary canal {tables Jj. to 10) 



a. Controls. As may be seen in tables 4 and 5, the absolute 

 weights obtained for the alimentary canal (empty stomach 

 and intestines, plus mesentery and pancreas) average slightly 

 lower than in Donaldson's tables corresponding to the older 

 males and females. In my younger rats, no data for this sys- 

 tem are available. The alimentary canal, including the stomach 

 and intestines when freed from the pancreas and mesentery, 

 weighs about 3 grams in the younger female rats (average 13 

 weeks old) and 4.1 grams in the males of the same age, forming 

 about 2.1 per cent of the net body weight in the former and a 

 little less in the latter (tables 8 and 9) . The measurements can 

 be made only approximately on account of the difficulty in 

 removing completely the contents of the canal without loss of 

 a part of the mucosa. No data for comparison with the digestive 

 canal without mesentery are available. 



h. Thyroid groups. The empty ahmentary canal appears 

 heavier in relative weight both in males and females of the older 

 thyroid groups than in the corresponding controls (tables 8 and 

 9). In no case is the difference very large, however, and owing 

 to variability and difficulty in securing exact weights of the 

 empty canal, the difference is of doubtful significance. Com- 

 pared by Donaldson's method, the increase in weight is about 

 12 per cent in each older group (table 10). 



c. Thymus, hypophysis, and pineal groups. The variations 

 observed in the • ahmentary canal of these groups (tables 6 to 

 9) in comparison with the controls are inconstant, and probably 

 wdthin the hmits of normal variability and experimental error. 



15. Suprarenal glands {tables Jf to 10) 



a. Controls. In absolute weight as compared with Donald- 

 son's norms, the suprarenals of my rats (tables 4 and 5) are 

 somewhat light in the case of the males, but correspond more 

 closely in the females. 



In relative weight (tables 8 and 9) my data correspond fairly 

 well with the results of Jackson ('13), but the suprarenals of 



