METABOLISM 



597 



Demonstration on Calcium Deficiency. Place two young white rats (40- 

 60 grams) in separate cages and feed the diets listed above. Make frequent 

 body weight determinations. The rat receiving Diet 2 will show normal growth. 

 The rat receiving Diet i will fail to show normal gains in weight. This diet is 

 deficient in calcium. See Fig. 187. 



7. Influence of Water Deficiency. (a) The importance of water in nutrition 

 may be shown very satisfactorily on guinea pigs. Proceed as follows: Place 



<:? 



ii 



. * 



th 



<fc 





1^22 



---4 



r wee/ts 2 4 62/0/2 



FIG. 187. GROWTH CURVE OF RAT WITH AND WITHOUT CALCIUM AND PHOSPHORUS IN 



THE DIET. 

 (Bergeim, Smith and Hawk: Unpublished data.) 



two young guinea pigs (150-200 grams) in separate cages, and give each free 

 access to a diet of hay, oats, and lemon or orange juice which has been dried 

 rapidly at a low temperature. Permit one pig water ad lib., and give the second 

 pig no water. The pig receiving water will remain normal and will exhibit normal 

 gain in body weight. The pig receiving no water will soon show pronounced 

 losses in body weight and other signs of abnormality. The animal will die in a 

 short time unless water is added to the diet. This experiment demonstrates 

 very clearly that water is an indispensable dietary constituent. In fact, water 

 is more important than food. The following experiment will show this : 



