164 Sanitary Stiidies of Baking Powders 



The data recorded for the pure sol. of aluminum and iron are those 

 obtained after a number of attempts in which the results did not ap- 

 proach the accuracy finally attained. With the small amounts of 

 aluminum and iron phosphates we did not experience the usual 

 trouble in washing the precipitate on the filter. 



From the data reported it is concluded that, for small amounts 

 of aluminum in the presence of iron and phosphates, the method 

 proposed by the Assoc. of Official Agric. Chemists, as modified by 

 Steel, gives values which are essentially the same in the case of Solu- 

 tions of pure salts of aluminum, but slightly lower when applied to 

 blood to which aluminum sulfate has been added, when compared 

 with the results obtained with the method of Schmidt and Hoag- 

 land and with the quantities of aluminum known to be present. 



