MINERAL METABOLISM 339 



Possibly the lack of some food accessory which affects mineral metabolism 

 (as for example the antiscorbutic vitamin) and which is reduced by dry- 

 ing, is reflected in the milk and results in the appearance of a pathological 

 condition in a young animal subsisting on that milk ( Baumann and How- 

 ard; Hart, Steenbock and Hoppert; Robb). 



The disturbance of phosphorus metabolism accompanying that of cal- 

 cium metabolism in rachitis has been considered a secondary effect. The 

 fact that phosphorus therapy is frequently successful (Kochmann(d) ; 

 Meyer (6) ) suggests that phosphorus may be more fundamentally involved 

 than it is generally thought to be. 



Osteomalacia, on the other hand, is more generally considered a disease 

 of calcium metabolism, occurring usually as a result of the drain on body 

 lime during pregnancy. McCrudden(c) considers that the normal "flux" 

 of calcium is increased in pregnancy, that because of functional inertia it 

 may continue too long after the demand has ceased, and become patho- 

 logical, and that ovariotomy effects a cure, not because of any functional 

 relation between the ovaries and Ca metabolism, but because it removes 

 the possibility of further drain on calcium by pregnancies. The effect 

 of castration on rats bears this out since the lime content of females is 

 unchanged by castration, but that of males is reduced 10-20 per cent 

 (Reach). 



