The Journal of experimental zoology . 319 319 296 312 222 217 206 203 365 320 319 304 322 227 219 207 210 395 326 319 301 339 230 217 207 213 425 328 323 301 352 234 213 204 220 455 321 318 296 349 236 211 204 218 the body growth of the animals as inbreeding advanced. Thefemales of the twenty-fifth generation (graph D) were, on thewhole, sHghtly heavier than were the females of the pi^ecedinggeneration group (graph C). Table 6 gives data showing the average body weights at differ-ent age periods of males and of females belonging to variousgeneration groups of the B series of inbreds. 80 HELEN
The Journal of experimental zoology . 319 319 296 312 222 217 206 203 365 320 319 304 322 227 219 207 210 395 326 319 301 339 230 217 207 213 425 328 323 301 352 234 213 204 220 455 321 318 296 349 236 211 204 218 the body growth of the animals as inbreeding advanced. Thefemales of the twenty-fifth generation (graph D) were, on thewhole, sHghtly heavier than were the females of the pi^ecedinggeneration group (graph C). Table 6 gives data showing the average body weights at differ-ent age periods of males and of females belonging to variousgeneration groups of the B series of inbreds. 80 HELEN DEAN KING The data given in table 6 served as the basis of constructionfor the graphs shown in figure 3 and in figure 4. A comparison of the graphs in figures 3 and 4 with the corre-sponding graphs in figures 1 and 2 shows that there was very httledifference between the two inbred series (A and B) as regards thebody-weight increase with age in the animals of the variousgeneration groups. In the B series, as in the A series, males and. Fig. 3 Graphs showing the increase in the weight of the body with age formales belonging to various generation groups of the B series of inbred rats (datain table 6; lettering as in fig. 1). females in the sixteenth to the eighteenth generation groups(graph A) were heavier animals at any given age than were thoseof subsequent generations; while the rats of the twenty-secondto the twenty-fourth generation groups showed a much lessvigorous growth than did the animals in the earlier rats in the twenty-fifth generation of the B series increasedin body weight very slowly during the adolescent period, as theposition of graph D in figures 3 and 4 indicates; but in the adult EFFECTS OF INBREEDING ON BODY WEIGHT 81 state their growth was much more vigorous, and their bodyweights, especially those of the males, compare favorably withthe weights of the animals in the group comprising the rats ofthe sixteenth to the eighteenth generations (graph A)
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1919
