1917] ANIMAL PRODUCTION. 267 



The growth and variability in the body weight of the albino rat, Helen 

 D. King {Anat. Rec, 9 (1915), No. 10, pp. 751-776, figs. 5).— The .luthor finds 

 that "when environmental conditions are uniform the growth of albino rats 

 within a given colony tends to follow the same course and to produce indi- 

 viduals having a like weight at any stated age. 



As a rule the male rat is heavier than the female at birth and also at all 

 subsequent ages at which records were taken. During the first 60 days of post- 

 natal life the body weight of the female tends to approach that of the male, but 

 after this age the male grows more rapidly than the female and soon greatly 

 exceeds her in body weight. At 200 days of age the male rat weighs, on the 

 average, about 70 gm. more than the female of the same age. The female tends 

 to increase in body weight at a much more rapid rate than does the male during 

 the early stages of development, and she reaches her maximum weight much 

 earlier than does the male. 



"The environmental and nutritive conditions under which rats are reared 

 have a marked influence on their body weights, as is indicated by the relation of 

 the growth graphs constructed from data obtained from three different series of 

 rats reared under different conditions. Variability in the body weight of the 

 albino rat, as measured by the coefficients of variation, is greatest when the 

 animals are about 60 days of age. It decreases slightly at 90 days, and after 

 120 days remains practically constant until the animals are about one year old. 

 Very young female rats seem to show as great a range of variability in body 

 weight as do the males, but the males are more variable than the females at 

 all later stages of growth. The average coefficient of variation for the body 

 weights of the 50 male rats used in this study is 13.6; that for the females 

 is 12.1. 



" In the rat there is apparently a direct correlation between the rapidity of 

 growth and the variability in body weight after the animals have reached 

 60 days of age. The records collected are not in a form to give evidence re- 

 garding the correlation that exists at earlier stages of growth. Fraternal 

 variability in the rat is less than racial variabllty. For the male rate the fra- 

 ternal variability is about 70 per cent that of the general population ; for the 

 female it is about 55 per cent." 



On the influence of exercise on the growth of organs in the albino rat, 

 S. Hatai {Anat. Rec, 9 {1915), No. 8, pp. 647-665) .—The author experimented 

 with the albino rat in order to discover the effect of long-continued exercise. 



" The heart, kidneys, and liver show an average excess of about 20 per cent, 

 while the spleen shows a similar amount of deficiency. The brain weight 

 shows an average excess of 4 per cent, while no change is noticed in the case 

 of the spinal cord. The ovaries give an excess of 84 per cent, while the testes 

 give an excess of 12 per cent. The hypophysis, as well as the suprarenals, 

 respond differently to exercise according to sex. Furthermore, these two 

 organs show, as the result of exercise, an approach to the relations charac- 

 teristic for the Norway rat. The exercised rats were either entirely free from 

 lung infection or but slightly affected. The control rats, on the other hand, had 

 badly infected lungs and in some series several of them were lost, presumably 

 from the lung disease. Analysis of the data shows that the lung infection is 

 not responsible for the changes observed in the organs." 



On the composition and physiological activity of the pituitary body, I, II, 

 F. Fengeb (Jour. Biol. Chem., 21 {1915), No. 2, pp. 283-288; 25 {1916), No. 3, 

 pp. 417-422). — The first part of this investigation was conducted for the pur- 

 pose of determining whether any seasonal variation exists in the pituitary 



