238 Aluminimn front Aluminised Foods [Dec 



sue analyzed by the method described above was first subjected to 

 oxidation.^ The weighed tissue was placed in a Kjeldahl flask and 

 concentrated nitric acid Solution added to it. The flask was heated 

 slowly at first and then more vigorously until the Solution became 

 clear, when a moderate excess of nitric acid Solution was added and 

 the liquid boiled down to a small volume. The fluid was then treated 

 with a fairly large volume of concentrated sulfuric acid Solution for 

 the expulsion o£ the nitric acid and the complete oxidation of any 

 residual organic matter. The sulfuric acid mixture was boiled for 

 at least two hours after it became colorless, in order completely to 

 eliminate NO2. The residue was then dissolved in water, made up 

 to volume, and the iron and aluminium determined as described 

 above. 



Condition of the animals throughout the experiments. The 

 experiments were conducted on four füll grown healthy dogs. The 

 feedings of aluminized bread were begun on June 29, 191 1, and in 

 each experiment were continued daily for about nine or ten weeks 

 until the day on which the dog was killed. All of the animals 

 appeared to thrive. They were weighed once a week. All of them 

 gained weight during the long periods of confinement in the cages. 

 The urine of each dog was collected every twenty four hours and 

 was measured. Aluminization of the food appeared to be without 

 eflfect on the daily average Output of urine. 



Operative procedure at the end of each of the main ex- 

 periments. The dog, in each case, was bled to death from the 

 femoral or iliac arteries. No general anesthetic was employed. 

 Cocain was injected in every case over the site of the vessel to be 

 exposed. None of the dogs showed any signs of pain during the 

 Operations. 



Tissues selected for analysis. The tissues or organs named 

 below were taken immediately after the death of the animal and at 

 once placed in large, thoroughly cleansed, wide mouthed glass stop- 

 pered bottles : Bile (and gall bladder), blood, bone (femur and a 

 piece of flat-bone from the skull), brain, heart, kidneys, liver, muscle 

 from the thigh, pancreas and spieen. Before removing the gall 

 bladder or the kidneys, they were tied oflF, so that no bile or blood 



'Steel: American Journal of Physiology, 191 1, xxviii, p. 97. 



