NUTRITION. 269 



mum is reached. Above this amount growth is not increased by increasing 

 the protein. Too much protein, e. g., 31 per cent, leads to digestive disturb- 

 ances and death. 



The minimal quantity of edestin necessary for normal growth is less than 

 of casein — an unexpected result in view of the chemical make-up of these 

 two proteins. 



The capacity to resume growth at a normal rate is long retained and has 

 been observed in one rat over 300 days old, an age at which very little 

 increase in weight occurs in normal animals. 



Depleted or stunted animals gain weight faster than the normal rate of 

 growth until they attain a size normal for their age. Thereafter they grow 

 at a normal rate. 



Attention has further been directed to a study of methods for estimating 

 the amount of each of the different types of protein contained in seeds. 

 This information is essential to the application of the results obtained by 

 feeding with the isolated individual proteins to feeding with entire seeds. 

 The results of this work are not yet ready for publication. 



The anaphylaxis experiments conducted in cooperation with Prof. H. G. 

 Wells have been continued and results of interest obtained which we hope 

 to publish soon. 



Much time and money have been expended under the present grant in 

 selecting and installing suitable apparatus for producing adequate quantities 

 of pure proteins and "protein-free milk." This became necessary when it 

 was decided to conduct the feeding experiments on an increased scale. 



This work required special studies of the methods to be employed for 

 making large quantities of pure proteins, and attention to the development 

 of these methods, after the new apparatus was put in use. 



A breeding department has also been established from which a supply of 

 vigorous rats of known age and parentage can now be obtained. Data are 

 also being collected as to the length of life and normal rate of growth on a 

 large number of animals, so that we shall soon have much more accurate 

 data than was before available. Such data are necessary for a proper judg- 

 ment respecting the outcome of the feeding experiments with artificial diets. 



The results of the year's work have appeared in the several papers, which 

 are listed in the bibliography, pp. 44, 45. 



PALEONTOLOGY. 



Case, E. C, University of Michigan, Ann Arbor, Michigan. Grant No. 

 772, allotted December 15, 191 1. Completion of work on the Permian 

 Vertebrate Fauna of North America. (For previous reports see Year 

 Books Nos. 2, 4, 8-10.) $2,000 



Since January 1, 1912, a study of the literature of the Red Beds of Okla- 

 homa, Kansas, Texas, New Mexico, and Colorado has been made ; the months 

 of July, August, and September were spent in the field in those States, study- 



l8 YB 



