78 



G. W. SALISBURY 



100 % N 2 



5 % C0 2 



12 3 4 



TIME -HOURS 



Fig. 10. Effect of pC0 2 on the anaerobic metabolism of bull sper- 

 matozoa in semen in IVT Na diluent at 37°C. Number of sperm samples, n, 

 equals 2; IVT is Illini variable-temperature diluent (Salisbury et aL, 1960). 



this time under 5% 00,-95% N 2 (Salisbury et aL, 1960). An even 

 more marked effect of K+ is noted with the washed cells. 



Inhibition by pC0 2 



Our observations on the effect of varying pC0 2 on anaerobic me- 

 tabolism of ejaculated bull spermatozoa have been published (Salis- 

 bury, 1959; Salisbury and VanDemark, 1957a, b; Salisbury et aL, 

 1960), and the historical development of the idea recently has been 

 reviewed (Salisbury and VanDemark, 1961). Typical results for 

 spermatozoa in semen are shown in Fig. 10 taken from Salisbury 

 et aL (1960). The figure shows an increasing inhibition of anaerobic 

 glycolysis with each increase in the pCO, to 100%. This is not al- 

 ways the case, however, since sometimes the inhibition is maximized 

 with less than 100% C0 2 ; this is particularly the case when the dil- 

 uent contains a high level of K+. 



Effect of pH on Livability under pCO, 2 Control 



It is well known that the pH of a bicarbonate solution varies with 

 the concentration of C0 2 in the atmosphere above it, and for any 

 given pC0 2 the pH varies directly with the bicarbonate concentration 



