78 



GROWTH IN PARTS 



Jackson and Lowrey conclude (p. 472) that the data indicate 

 no noteworthy differences between the sexes in the relative weights 

 of the various parts and systems, and that the body of the al- 

 bino rat has practically reached the adult proportions in its com- 

 ponent parts and systems at the age of ten weeks. 



Corresponding observations, though less extensive, made on 

 the Norway rat are given in chapter 12. 



TABLE 52 



Giving the percentage values for the cartilaginous skeleton when this has been pre- 

 pared by maceration (Conrow, MS. '15), also giving by difference between these 

 values and those in table 50 the percentage values for the "periosteum, ligaments, 

 etc." 



Weight of entire cartilaginous skeleton. Using a 2 per cent so- 

 lution of the commercial gold dust washing powder ('Gold dust 

 washing powder' consists of about 45 per cent sodium carbonate, 

 30 per cent soap powder, and 25 per cent water), the skeletons 

 of some 70 inbred Albinos (King) have been carefully prepared 

 by Conrow (MS '15) at The Wistar Institute. The animals 

 were reared on a scrap diet. A careful comparison with the stock 

 Albinos has not yet been made, but at the same time there is no 

 suggestion thus far that the values for the inbreds differ from 



