Perloline is shown to be a normal constituent of perennial rye-grass growing in Britain.Perloline is shown to exist in different solvents as an anhydronium base, a pseudo-base, or an ether thereof, as a cation, or as an anion.IN 1941 Melville and Grimmett reported the presence of a yellow, fluorescent alkaloid in perennial rye-grass (Lolium perenne L.) growing in New Zealand, and called this base Per1oline.l The alkaloids of this grass have formed the subject of a number of Papers dealing with the extraction of perloline and other bases from the grass,2 the estimation of alkaloids in the grass,3 the characterisation and chemistry of perl~line,~ its toxicity and physiological effect^,^ its effect on plant growth,6 and the effect of genetic differences on the perloline content of rye-grass herbage.7 Besides perloline, a colourless fluorescent base has been characterised and called perlolidine; 2 ~p k 8 a volatile base and a red, fluorescent basic fraction have been d e ~c r i b e d , ~J b ~~ the last two not being fully characterised. Surveys of other species of grass grown in New Zealand showed that perloline was also present in Lolium temulentum L., Festuca arundinacea Shreb., and Setaria lutescens (Weigel) F. T. Hubb; it has also been reported in Lolium multiforum Lam., Dactylis glomerata L., and Phleum pratense L.2c94c In Lolium perenne the alkaloid was present chiefly in the stems, and then only in the summer.The writer has detected perloline spectroscopically in an extract from L. $eren?.te growing wild in Leeds during May (but not during the previous December) and isolated it from this grass growing wild at Barnet, Hertfordshire during July, and on a much larger scale from hay from a pure strain of Lolium perenne grown at Auchincruive, Ayrshire, harvested in the early summer. Paper chromatography of the bases from the last two sources showed that there were more alkaloids in the grass than had been previously reported. The chromatogram could be divided into ten zones, one of which is perloline. Preparative chromatography on columns has shown that some of these zones contain more than one base. The overall yield of 490 mg. of perloline from 52 kg. of hay (10 p.p.m., corresponding to about 2 p.p.m. in the grass) is low compared with that reported from New Zealand. Some perloline may have been destroyed in the hay-making (another sample of this grass, dried by hot air, contained traces only of perloline); also, the hay contained basic material which, though not perloline, gave a yellow solution in chloroform, with a green fluorescence. If this material is present in the fresh grass, then the published colorimetric method for estimating perlolineThe workers in New Zealand published analyses for perloline and derivatives, and assigned to the base the formula C4,H,N407 containing 2 basic nitrogen atoms, 4 methoxyl groups, and one acetylateable hydroxyl group. No degradation product of known