58-t 



rng% Bone Biopsies "A 



belangf:r, robichon, migicovsky, copp, vixgknt 



Bone Biopsies B 



8 



10 



12 



14 



16 



18 



Time in Hours 



Fig. a. Changes in plasma calcium and phosphorus during intravenous in- 

 fusion of EDTA into a 2.3-kg dog. The infusion removed 2.2 gm calcium 

 from blood during the 12-hour period, inducing hypocalcemia and presumablv 

 stimulating endogenous parathormone production. The initial control bone 

 biopsies were taken as indicated at "A" and the postinfusion bone biopsies 

 were taken at "R." Parathxroidectomv was performed as indicated b\^ PTX. 



Histology 



Chicks and rats. One bone from each of the chicks and rats of 

 all groups was demineralized in EDTA as above. The other tibia 

 was embedded in low-viscosity nitrocellulose without demineraliza- 

 tion. 



Dogs. Portions of the metaphysis of the tibia and a portion of 

 the parietal bone as well as a variety of other bones in group 3 were 

 cut with a ]:»and saw and fixed for 24 to 48 hours in neutral formal- 

 dehvde. 



