506 



Scientific Proceedings (132) 



Abstracts of Communications. 

 Thirteenth meeting. 



Minnesota Branch, Minneapolis, Minnesota, May 9, 1923. 



250 (2210) 



Growth and reproduction of rats on whole milk as the sole diet. 

 By LEROY S. PALMER and CORNELIA KENNEDY. 



[From the Section of Animal Nutrition, Division of Agricultural 

 Biochemistry, University of Minnesota, St. Paul, Minn.] 



Several investigators have observed the effects of rearing rats 

 on milk diets. Matill 1 and co-workers especially have studied 

 this problem, using dried milk or concentrated solutions of milk 

 powder for the most part in their experiments. 



We have made a limited study of this problem with the fol- 

 lowing results. Using fresh, raw liquid milk exclusively 2 we 

 have successfully raised 3 male albino rats to full size at maturity, 

 beginning at weaning. This trial was begun August 10, 1922. 

 Each rat was kept in a separate cage with one-quarter inch mesh 

 wire bottom without bedding. The consumption of milk solids 

 by these rats has varied between 35 and 100 grams per week per 

 rat. These rats, however, on repeated trials have failed to ex- 

 hibit any mating instinct when placed with females from our 

 breeding colony, which were known to be in heat. 



In a second experiment begun October 24, 1922, two colonies 

 of rats, each containing 5 rats, with both sexes represented, on 

 wire bottom cages, have not attained the expected size at maturity 

 on the fresh, raw, whole milk diet. Growth was normal for the 

 first 50 to 70 days only. The calculated average consumption 

 of milk solids for each rat has not been as high as in the case 

 of the rats in Experiment 1, kept in separate cages. The females 

 have so far been entirely barren, confirming Mattill's results. 



In a third experiment 3 female rats reared to partial maturity 

 on mixed diet, each having reared one litter, were placed in 



1 J. Biol. Chem., 1920, xliv, 137-157; 1923, lv, 443-455. The literature is 

 thoroughly reviewed in these papers. 



2 Our rats, however, had access to distilled water containing iodin. 



