STUDIES ON TTIE METABOLISM OF I'lIOSPHOKl S IN' ANIMALS 



165 



Tahm; 11 



KilkMl 



Jj. c. froiu tlic rM(l. I' lukcii 

 foiiiiil ill 1(111 iiigm iislies 



Bones 



Incisors 



Mclar.-5 



Liver 



\\'ei(^lit ill mem 



Bones' 

 I (legs) 



Incisors Molars 1 Liver 



I Week 



1 „ . 



2 Weeks 

 2 



3 



3 ., 

 3 „ 



135 

 103 



86 



84 



1(58 



145 



205 



The above l)one figures show a marked dii'ference as compared with 

 normal rats of the same age (cf. Table 6). We are engaged in carrying 

 out further experiments on rats with rickets. 



GENERAL CONSIDERATIONS 



The rapid entrance of the labelled phosphorus into the bone is in no 

 way puzzling. If solid calcium phosphate, one of the chief constituents 

 of the bone, is in contact with the solution containing labelled phosphate 

 ions a rapid distribution of the latter takes place between the surface 

 of the solid phase and the liquid phase, as was seen from the following 

 experimeni . 3950 gm freshly precipitated Ca3(P04)2 were shaken 

 with 5 cc. of water saturated with C'a3(P04)2 at room temperature 

 and containing an infinitely small amount of labelled sodium phosphate. 

 After lapse of four hours 84.1 per cent of the labelled phosphate ions 

 were found in the solid phase and only 15.9 per cent in the solution. 

 The calcium phosphate of the bone tissue being in a very intimate con- 

 tact with the blood stream, i.e. with cells containing labelled phosphate, 

 a similar exchange to that described above will take place between 

 the unlabelled phosphate of the bone and the labelled phosphate present 

 in the liquid phase. 



Beside the above mechanism we have to consider two others jusi 

 as important. During growth, the bone tissue formed will be buill 

 up from labelled phosphorus as long as the blood stream contains 

 the latter. 



Finally we have to envisage a third possibility, namely the entrance 

 of labelled phosphorus into the bone through a constant break-down 



1 The weight of the total skeleton is obtained by dividing the figures obtained 



for \hv legs by 0.2(>. 



