CHAPTER 8 



< 



GROWTH IN TERMS OF WATER AND SOLIDS 



1. In the body as a whole. 2. In the larger divisions of the body and the 

 organs. 3. In the brain and spinal cord. 



Water and solids 1) in the body as a whole and 2) in the larger 

 divisions and the organs. Data on this head have been pub- 

 lished by Lowrey ('13) and are here presented. 



With the exception of one of the old rats the animals used for 

 the following table 75 were reared at the University of Missouri. 

 They were fed on chopped corn with a daily ration of bread soaked 

 in whole milk and once a week a small quantity of fresh beef 

 was given them. All were sound except some of the older ani- 

 mals which suffered from infected lungs but not to such a de- 

 gree as to affect their general nutrition or vigor. Table 75 is 

 based on table 1, Lowrey ('13). The data for the two sexes are 

 combined. In the original the range of the observations is given 

 and also the number of animals used in each instance. In the 

 present table the ranges are omitted and the number of animals 

 is given for the body weight (net) only. The other determina- 

 tions for the systems and organs were based on about the same 

 number of animals as were used for the body weight, except in 

 the case of the testes where the numbers are about half as large. 

 The oldest animals were somewhat under one year of age. 

 3) Percentage of water in the brain and spinal cord. Using stock 

 rats from the colony at The Wistar Institute, the percentage of 

 water has been determined for the brain and spinal cord by Don- 

 aldson (MS '14). The values obtained by this study replace 

 those previously published. (Donaldson '10.) The methods of 

 removal are given on page 90. The rats were reared on a 

 scrap diet. The fresh brain or cord was weighed in a closed 

 bottle, then dried at 90-95C. until the dried weight was con- 

 stant and the difference taken as the amount of water. 



176 



