220 



RUTH WHEELER 



The growth on milk food of varying protein- and ash-content 

 was significant from several standpoints. Chart 5 shows the in- 

 crease in body weight on three milk foods whose composition 

 is given in table 1. The numbers on the chart correspond with 

 those in the table. The upper interrupted line is a composite 

 of the growth charts of all the control mice on mixed food; the 

 lower (dotted) line, of only such controls as were related in origin 

 to the mice on the three milk foods represented in the chart. 



25 



20 



o 



ro 



10 



20 

 Days 



40 



Chart 5 Showing the comparative growth of three mice on milk foods vary- 

 ing in protein and ash content. The dotteS lines represent the normal curves 

 of growth. 



A comparison of chart and table shows that the rate of growth 

 and the final weight attained increased with the percentage of 

 salts and of protein, until when the protein was 30 per cent and 

 the ash 6.8 per cent^^ both growth and final weight were compar- 

 able with those of the controls. The similarity is even greater if 

 only controls of related origin are considered — as in the lower 

 dotted line.i'' 



The curves on chart 6 taken from the publications of Osborne 

 and Mendel indicate the growth of rats on mixed food (normal 



'« Milk food III in the table. 



1' The mice represented in th lower dotted line and in line iii grew as did the 

 others, but they were evidently of a small variety. 



