The metabolites of piperic acid and some related compounds in the rat.

specific concentration or orientation previously proposed. 4. The inhibitory effects were much reduced by the presence of phosphate or by preincubation with 5 mm-i8ocitrate. 5. In the presence of sodium chloride the activity of the aconitase increased. With potassium chloride there was an increase followedby a fall. An increase in the concentration of both salts much reduced the inhibition of fluorocitrate. 6. The percentage inhibition with fluorocitrate was the same for L8( + )-i8ocitrate (D), though the rate for a given amount of i80citrate was doubled. There was no indication that the inactive isomer was an inhibitor. 7. Variation of temperature within +40 was about 4% per degree. Variations in pH of + 0*6 caused little change in fluorocitrate inhibition, though a fall in activity was found on making more alkaline.