ALBINO EAT VISCERA, GLANDS, EYEBALLS! WEIGHTS 111 



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Chart 11 Showing the weight of thjToid gland of the albino rat according to 

 body weight. The observed weights are represented by 42 (Jackson) female rats, 

 below .50 grams in body weight, and 49 (Wistar) male rats, above 50 grams in body 

 weight; and 36 (Jackson) female rats, below 50 grams in body weight, and 27 (Wis- 

 tar) female rats, above 50 grams in body weight. 



• Observed weight, male. Calculated weight for both se.xes. 



O Observed weight, female. 



11. Thyroid gland. Unlike the two ductless glands already 

 mentioned, the thyroid gland does not exhibit any weight differ- 

 ence between the two sexes. The growth of the thyroid gland 

 in weight is represented by the following formula: Weight of 

 thyroid = 



0.0000973 (Bd. wt. +27) + 0.0139 log (Bd. wt. + 27) -0.0226. 



The constants of the formula were determined from 91 males 

 and 63 females. The relation between calculated and observed 

 values is shown in chart 11. We notice in the chart that the 

 two sexes do not differ fom each other, as the observed mean 

 values for the two sexes are not segregated and those for both 

 sexes cluster round the theoretical line. 



The thyroid gland is the most variable among all the ductless 

 glands treated in the present paper. The variation is due to cases 



