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RUTH WHifeLER 



made. The lower curve in chart 1 shows a typical case. In this, 

 as in the subsequent charts, body weight in grams is plotted on 

 the ordinates, time in days on the abscissae. The abbreviation 

 'pfm.' is used to indicate 'protein-free milk.' The inorganic in- 

 gredients of the dietaries in the successful experiments were 

 furnished in the form of the 'protein-free milk'" of Osborne and 

 Mendel, made by removing the fat and proteins from milk 

 and leaving chiefly lactose and salts, except sodium chloride, in 



Chart 1 Showing the steady loss of weight of mice on salt-free casein food or 

 on casein food containing Rohmann's salt mixture (R. salts) followed by rapid 

 recovery when casein food containing protein-free milk (casein -\- pfm.) is given. 



the same relative amounts, as in milk itself. In chart 1 the 

 upper line shows the rapid decline of a mouse on salt-free food 

 and the immediate recovery that took place when protein-free 

 milk was employed. This experience, as well as the fact that for 

 months at a time mice throve on food in which 'protein-free milk 

 was the only source of salts, indicates that they find in it in 

 available form all the inorganic constituents necessary for their 

 maintenance for long periods. 



" Ibid, Part II, p. 82. 



