226 



GROWTH OF PARTS AND ORGANS 



Tables for the increase in the length of the tail, in the weight of 

 the entire body, and in the weight of several of the viscera accord- 

 ing to body length — tables 144-148 and 152. 



Also a series of crude tables giving the directly observed weights 

 of a series of small organs on body weight and age — tables 

 149 and 150. 



Jackson ('13) and others have called attention to discrepancies 

 between their observed values and those in table 148. 



TABLE 143 



Coefficients of correlation of organ weights with the body weight: albino rat at 



different ages. Arranged according to mean values in the last 



column (Jackson, '13) 



Head 



Kidneys 



Liver 



Lungs 



Brain 



Heart 



Testes 



Ovaries 



Intestinal canal 

 (plus contents). 



Thymus 



Spleen 



Eyeballs 



Suprarenals 



Average 



0.86 

 0.86 

 0.83 

 0.80 

 0.78 

 0.78 

 0.75 

 0.75 



0.62 

 0.60 

 0.55 

 0.45 

 0.40 



0.70 



On careful consideration it appears that the values in the 

 tables are those characteristic for the special strain which was 

 used, and the original table values have therefore been retained 

 unaltered. That other strains may give other values is of course 

 to be recognized and also the high variability of these organs, 

 especially the endocrine glands, must always be kept in mind. 



Table 151 for the weight of the thymus — is based not on body 

 length but on age. 



Weight of all the viscera combined — table 153. 



