15(S ADVENTURES IN RADIOISOTOPE RESEARCH 



obtained was then introduced under the Geiger counter. 19 days later 

 the rat, which weighed 256 gm, was killed, the corpse was treated 

 with fuming nitric acid to destroy organic compounds, the fatty residue 

 was treated with cone, sulphuric acid, and then ignited in an electric 



Table 3. — L.jmgm Radioactive Calcium Phosp- 

 hate ADDED TO Normal Diet of Adi'lt Rat 



Number of days after 

 taking rad. P 



Percentage of original rad. P 



in the urinu in the faeces 



11.4 13.1 



3.9 4.7 



2.7 2.4 



0— 3 



3— 7 



7 — 10 



10—13 j 1.8 0.93 



13—16 



16—19 



Total . . 



1.3 1.1 



1.2 1.88 



22.3 24.0 



' Faeces contaminated by urine. 



oven. 50.2 per cent of the phosphorus given was found in the ashes, 

 which were to a large extent composed of calcium phosphate, and had 

 a total weight of 5.84 gm. 



In some cases we added large amounts of calcium phosphate contain- 

 ing active phosphorus to the diet. When for example 18 mgm of phos- 

 phorus as calcium phosphate were given — this corresponds to about 

 four times the phosphorus present in the normal diet — 41 per cent 

 of the active phosphorus was eliminated through the gut in the course 

 of 19 days and only about 10 per cent through the kidneys. Furthermore 

 an analysis of the active phosphorus content of the corpse and the 

 excreta revealed that when large amounts of phosphorus were added 

 to the diet the animals would eat only part of it, however, carefully 

 it was administered. We decided therefore to study the effect of the 

 intake of large amounts of phosphorus on dogs. 



The phosphorus atoms absorbed have ample opportunity to enter 

 into kinetic exchange with the phosphate ions present in muscles, 

 bones, and other organs and also to a certain extent to enter organic 

 molecules and replace the phosphorus atoms present there. Many of the 

 last mentioned processes are dependent on enzymatic action. The rate 

 at which the active phosphorus enters the blood corpuscles, the parti- 

 culars of this process, and the distribution of the radioactive phosphorus 

 between the blood and the different organs were investigated by Pro- 

 fessor LuNDSGAARD and one of us and the results will be published 

 shortly. 



