EFFECTS OF INBREEDING ON BODY WEIGHT 



31 



Figures 11 and 12 show graphs for weight increase with age 

 in two series of stock albinos (graphs A and C), together with 

 graphs representing the growth of animals in the inbred series 

 (graphs B and D). The graphs for the various groups of males 

 are given in figure 11. 



4 i-( '(--(-iGrowth in body weight. Albino Rat, 



IjiijliltJIilM^ 



280,300 320 340 360 380 400 420 440 460 480 



Fig. 11 Graphs showing the increase in the weight of the body with age for 

 different series of male albino rats. A, graph constructed from Donaldson's 

 data for stock albinos; B, graph for males belonging in the seventh to the fif- 

 teenth generations of the two series of inbreds combined; C, graph constructed 

 from data for a selected series of stock albinos used as controls for the inbred 

 strain; D, graph for males belonging in the first six generations of the two series 

 combined. 



In figure 11 graph B, representing the growth of the males in 

 the inbred series, runs higher than Donaldson's graph for stock 

 albinos (A) from the beginning until the end of its course. At 

 the 243 day period the space between these graphs represents a 

 difference of about 18 per cent in the average body weights of 

 the two series of animals. At all points, except the thirty day 

 period, graph B is higher than graph C which shows the body 



