Observations upon the toxic principle in the seeds of Dichapetalum toxicarium; separation of a long-chain fatty acid containing fluorine.

F3 and F4. Both of these were active in reducing the R.Q. in vitro (Table 1) but only one (F4) possessed growth-promoting activity. Since some pituitary preparations with intermedin activity (Colip, 1938; Folley, 1955) have been found to possess also an R.Q.-lowering action, Dr H. B. F. Dixon kindly tested some of our preparations for melanocyte-stimulating activity in frogs and found no relationship between the small amount of intermedin-like activity observed and the R.Q.-reducing activity.