1^*6J ANIMAL PRODUCTION. 865 



"There is a steady decrease in the percentage content of alcohol-soluble 

 phosphorus in the tissues (other than cerebral tissues) of mice from birth to 

 210 days of age, and this decrease is almost exactly in direct proportion to 

 their age," 



III. The influence of the anterior lobe of the pituitary body vdoh the groioth 

 of the white mouse (pp. 3S.5-396).— It was found that "the administration of 

 0.125 gm. per day per animal of fresh anterior lobe pituitary tissue to mice, 

 beginning at 4 weeks after birth (conclusion of the second growth cycle) leads 

 to retardation of growth during the earlier portion of the third-growth cycle, 

 between the sixth and twentieth weeks. In the latter part of the third-growth 

 cycle, however, from the twentieth to the sixtieth weeks after birth, the growth 

 of the pituitary-fed animals is markedly accelerated, so that they not only 

 catch up to the normals, but actually, at about one year of age, come to surpa.ss 

 the normals in weight. 



" The effect of the pituitary tissue upon the variability of the weight of the 

 animals is similar to its effect upon the velocity of their growth. The varia- 

 bility is diminished in the earlier portion of the third-growth cycle, particularly 

 between the tenth and the twentieth weeks. Between the twentieth and the 

 sixtieth weeks, however, the variability curves of the pituitary-fed animals ap- 

 proach the variability curves of the normals, and at about the fortieth or 

 riftieth week the two variability curves intersect. 



" Pituitary-fed animals, from about the thirtieth week onward, appear more 

 compactly buiit than normal animals. The pituitary-fed animals, weight for 

 weight, are smaller than the normals of the same age, and size for size they are 

 heavier. Pituitary-fed males are noticeably more belligerent in their habits 

 than normal males." 



IV. The influence of tethelin, the growth-controlling principle of the anterior 

 lobe of the pituitary body, upoti the growth of the tvhite mouse (pp. 397-408). — 

 From the concentrated alcoholic extract of dried anterior lobes of ox pituitaries 

 a substance has been extracted and named tethelin. 



" The effects of tethelin upon the growth of white mice resemble in every par- 

 ticular the effects of the administration of the whole anterior lobe. These 

 effects consist in marked retardation of the first portion of the third growth 

 cycle followed by acceleration of the latter portion of the third growth cycle. 

 The variability in weight of the tethelin-fed animals, like that of the pituitary- 

 fed animals, is less than that of normals of the same age. Adult tethelin-fed 

 animals, like adult animals which have been fed upon the anterior lobe of the 

 pituitary body, are more compact in form and build than normal animals of 

 the same age. Weight for weight the tethelin-fed animals are smaller than the 

 normal ones, and size for size they are heavier. The coats of adult male ani- 

 mals which have been fed with tethelin retain, even at 14 months of age, the 

 glossy silky appearance of the coats of young animals. Normal males, even 6 

 months prior to this age, have shaggy, staring, and discolored coats. This im- 

 provement in the coat was not observed in the pituitary-fed animal. Tethelin- 

 fed animals do not display the remarkably enhanced belligerency which is 

 exhibited by pituitary-fed animals." 



Y. The influence of cholesterol upon the growth of the uhite mouse (pp. 

 635-646). — It was found in these studies that "the administration of 40 mg, 

 per day per animal of cholesterol to mice, beginning at five weeks after birth 

 (conclusion of the second growth cycle), leads to marked retardation of growth 

 during the earlier portion of the third growth cycle, between the fifth and tenth 

 weeks. From the tenth week onward, however, growth is decidedly accelerated, 

 although the acceleration is insufiicient to compensate entirely for the initial 

 retardation. The influence of cholesterol upon the third growth cycle in mice is 



