82 



GROWTH IN PARTS 



TABLE 54— Concluded 



Tests show that after 30 days of age, drying at room tempera- 

 ture causes less than one per cent of shrinkage in the absolute 

 lengths of the bones. The values for the bone lengths given in 

 the table are means for the right and left sides — the length for 

 the two sides usually being very nearly the same. The 

 body length in every case is taken on the rat immediately after 

 chloroforming. 



Weight of cranium. Determinations of the weight of the 

 cranium dried at room temperature have been made, Donald- 

 son ('12 a). By the cranium is meant the skull with upper 



