018 



p. GOLDHABER 



balanced salt solution containing penicillin and streptomycin) we 

 have been able to demonstrate a dramatic, clear-cut effect of Lilly 

 parathyroid extract in roller-tube cultures gassed with 50 per cent 

 O2. This finding differed from our previous results in that resorption 

 did not cease after approximately 5 davs, but continued until prac- 

 tically all the bone was destroyed. The gross, massive bone resorp- 

 tion resulting from the addition of 0.5 unit of parathyroid extract 

 per ml of medium every 2 days for 15 davs mav be seen in Fig. 23. 



Fig. 23. Gross appearance of 15-day cultures. Both control and experimental 

 roller tubes were gassed with 50 per cent Oo. Note almost complete resorption 

 of calvaria in tubes containing 0.5 unit of Lilly parathyroid extract per ml of 

 medium (80 per cent horse serum + 20 per cent Gey's balanced salt solution). 



It should be noted that both the control and experimental groups 

 were gassed with 50 per cent Ol'. Evidence that this effect was due 

 to the hormone per se rather than to some contaminant in the com- 

 mercial parathyroid extract was obtained by the use of more highly 

 purified parathxroid preparations" which gave similar results. 



" Kindly pro\ ided by Dr. Paul L. Muiison. 



