No. 645] . ALCOHOL AND WHITE EATS 305 



cells liberated, while the somatic condition of the mother 

 plays a part in determining whether or not a litter will be 

 produced. The results from litter size agree strikingly, 

 qualitatively and even quantitatively with those of Stock- 

 ard and Papanicolaou from similar studies with guinea 

 pigs; the results from the number of litters agree with 

 Pearl's on fowl in so far as they may be interpreted by 

 assuming a selective action of the alcohol working upon 

 existing genetic differences. In the fowl the alcohol ap- 

 pears to select betw^een germ cells ; in the rats it appears 

 to select between mothers of different physiological and 

 genetic grades. 



Weight 



The data on weight (see MacDowell, '22b) form an ex- 

 tensive series consisting of weekly weighings of practical- 

 ly all the rats raised in the various generations herein de- 

 scribed. Individual growth curves were plotted and from 

 these the weights at six ages were taken for statistical 

 study. This procedure was necessitated by the fact that 

 all the rats were weighed on the same day each week, so 

 that the rats were of dilferent ages. The results are 

 based primarily upon the males (see Table II), since the 

 pregnancies of the females make their data less reliable. 

 However, when the data from the females with arbitrary 

 smoothing of the pregnancy peaks are summarized, the 

 results so obtained support those given by the males. 

 Each of the four strains shows that the treated rats grew 

 more slowly than the controls. This is an influence shown 

 by the population as a whole, although there are some 

 individual treated males that remained as heavy as the 

 heaviest controls. The untreated offspring of the treated 

 rats tended to grow more rapidly than their controls. 

 This result is not so clear as the opposite result in the 

 preceding generation ; the absolute differences are not so 

 large and the strains do not show this in equal measure. 

 Treated rats from treated parents barely ditfer at all 

 from their controls. Very little can be concluded from 

 the weights of the untreated offspring from untreated 



