EXCH.\N(iE OF PHOSPHOllUS IN' TEKTIL 



183 



EXCHANGE OF PHOSPHORUS IN THE TEETH OF CATS 



"N! 



For the teeth of young cals^ killed a few hours afler Ihc subcutaneous 

 injection of the labelled phosphorus the results seen in Tabl(> 17 and 

 18 Avere obtained. 



T.A.Br.K 17. Cat VVkichi ntj 2 kgu Killkd aktkh 31/2 Hours 



Table 18. Cat Weighing 2.5 kgm., Killed after U/j Hoitr.s 



We also investigated fully grown cats. A cat weighing about 4.5 kgm 

 and killed three days after administration of the labelled P gave the 

 figures seen in Table 19. In this experiment the labelled P injected was 

 not of negligible weight but amounted to 15 mgm (corresponding to 

 about 75 mgm sodium phosphate). The labelled phosphorus used in 

 this experiment was kindly presented to us by Prof. Lawrence and 

 was prepared by the action of high speed deuterium ions on phosphorus 

 and accordingly contained a comparatively large amount of normal 

 phosphorus. The injection of 15 mgm P into a cat leads to an 

 accelerated excretion and the figures are thus not entirely comparable 

 with those of the last described experiment, which was furthermore 

 carried out on a growing cat. 



^ The heads of the eats were kindly given to us by Professor Lundso.a.aj{I): 

 they were obtained in the course of an investigation on the distribution of labelled 

 phosphorus carried out by him and one of the present writers. In the first men- 

 tioned case 1 mgm plasma P was found to contain after Si/o horn's 1.0% of the 

 activity injected, i. e. about 2300 times as much as that present in 1 mgm of tlu> 

 upper molar P. 



