POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH. 99XIL-The Constitueuts of Colocyntk.By FILEDERICK BELDING POWER and CHARLES WATSON MOORE.UNDER the title of ‘‘ Colocynth ” the various national Pharmacopceinsrecognise the dried, peeled fruit, or the dried pulp of the fruit, ofCitrullus Colocynthis, Schrader. Although this f r u i t has been usedmedicinally for a very long period, and has been the subject of severalinvestigations, no complete chemical examination has hitherto beenmade of it, and the various products described in the literature ashaving been obtained therefrom were either amorphous or of anindefinite nature. It was recorded, for example, many years ago byWalz ( N . Jahrb. Pharm., 1858, 9, 16, 225; 1861, 16, 10) thatcolocynth contains a bitter glucoside, designated ‘‘ colocynthin,” which,although usually forming a yellow, amorphous mass, could be obtainedin a crystalline state by the slow evaporation of its alcoholic solution.H 100 POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH.This so-called colocynthin, to which the formula C,,H,,O,, wasassigned, was stated to yield, on heating with dilute acids, dextroseand “ colocynthein,” tho latter having been described as an amorphousresin. The same investigator noted the occurrence of a tasteless,crystalline substance, designated ‘‘ colocynthitin,” which was found tobe insoluble in water and cold absolute alcohol, but soluble in boilingalcohol and ether, although its characters do not appear to have beenfurther determined.Henke (Arch. Pharrn., 1883, 221, 200) couldobtain a product corresponding with colocynthin only in the form ofa yellow, amorphous powder, and was unable to confirm the state-ment respecting its glucosidic character.Johannson (Zeitsch. anal.Cliem., 1885, 24, 154) has stated that colocynthin, when heatedwith dilute sulphuric acid, yields colocynthein, elatsrin, and bryonin,”and he recorded some colour reactions which were supposed t odifferentiate these products,Naylor and Chappel (Pha~m. J., 1907, [iv], 25, 117), in a paperentitled : ‘‘ On Cucumis trigonus, Roxb., and Colocynthin,” have com-pared a product obtained by them from the fruit of the above-mentionedspecies of Cucunais, indigenoils to India, with the so-called ‘‘ colocyn-thin” obtained from colocynth by Henke’s method and by a,modification of the latter.It is stated that whilst the productobtained from either the Indian fruit or from colocynth by Henke’sprocess was amorphous, ‘‘ that resulting from the modified processwas most largely deposited on spontaneous evaporation of its solventin pale yellow needles.” They were thus led to conclude, in the firstplace, that ‘‘ colocynthin prepared from CitrulZus Colocynthis may beobtained in a crystalline state, despite the failure of Henke and ofWagner t o induce it to assnme a crystalline form ” ; secondly, thatnotwithstanding the doubts cast by Henke upon its decomposition byacids into colocynthein and a sugar, their results on the contraryconfirm those of Johannson (Zoc. cit.), that colocynthin is capable ofhydrolysis, and that it yields, amongst other products, colocyntheinand elaterin, t o which they may add-and a sugar, dextrose.Thesame authors furthermore state that (‘ colocynth contains a white,crystalline body, agreeing in its general characters with the colocyn-thetin (colocynthitin) of Walz.” There is, however, no evidence thatany of the products prepared and examined by Naylor and Chappelwere pure or homogeneous substances, and their comparison of themwas chiefly restricted to certain colour reactions which are by nomeans characteristic of the substances they are supposed to identify.On the other hand, it may quite safely be assumed that.the productsreferred to were very indefinite mixtures.The present investigation has shown that colocynth contains aconbiderable amount of a-elaterin (Trans., 1909, 95, 1989), whicPOWER AND MOORE: TEE CONSTITUENTS OF COLOCYNTH.101is present in the free state, together with other .compounds whichhave not previously been isolated. A complete summary of the resultsnow obtained, with the deductions from them, is given at the end ofthis paper.EXP E RIM E NTA L.The material employed in this investigation was Turkish colocynth,consisting of the dried, peeled fruit of Citrullus Colocynthis, Schrader.The original weight of this material was 103 kilograms. Afterseparating a8 completely as possible the seeds from the pulp, thelatter was found to weigh 25.6 kilograms, or 24.4 per cent. of thewhole. The seeds amounted to 79.3 kilograms, thus representing75.5 per cent.of the weight of the entire peeled fruit.A small portion (10 grams) of the above-mentioned pulp wassubjected to the test for an alkaloid, when reactions were obtainedindicating the presence of an appreciable amount of such a substance.A. further portion (20 grams) of the ground pulp was extractedsuccessively in a Soxhlet apparatus with various solvents, when thefollowing amounts of extract, dried at looo, were obtained.Petroleum (b. p. 35-50") extracted 0'33 gram = 1.65 per cent.Chloroform ,, 1-06 ,, = 5.30 ,,Ethyl acetate ,, 0.61 ,, = 3.05 ,,Alcohol ,, 0'92 ,, = 4'60 ,,Ether ,, 1'75 ,, = 8.75 ,,- -Total . .. .. . ... . . . 4.67 grains = 23'35 per cent.For the purpose of a complete examination, 24.6 kilograms of theground colocynth pulp were completely extracted with hot alcohol.After the removal of the greater portion of the alcohol, a viscid, dark-coloured extract was obtained, amounting to 6.63 kilograms,DistiZlation of the Extract with Steam.A quantity (2 kilograms) of the above-mentioned extract, represent-ing 7.42 kilograms of the pulp, was mixed with water, and steampassdd through the mixture for several hours, The distillate,which amounted to 4 litres, contained some drops of oil floating onthe surface.It mas extracted with ether, the ethereal liquid beingwashed, dried, and the solvent removed, when a small quantity of anessential oil was obtained. This was a pale yellow liquid, whichpossessed a characteristic odour, and, after some time, deposited asmall amount of a crystalline substance.The amount of this oilwas, however, too small to permit of its further investigation102 POWElt AND MOORE: THE CONSTITUENTS OF COLOCYNTH,Non-volatile Constituents of the. Extruct.After the distillation of the extract with steam, as described above,there remained in the distillation flask a dark-coloured, aqueous liquid(A) and a quantity of a brown resin (B). The latter was collected andrepeatedly washed with water until nothing further was removed, thewashings being added t o the above-mentioned aqueous liquid.Examination of the Aqueous Liquid (A).Isohtion of a New Dihydric AZcohol, Citrullol, C22H3602(OH)2.The aqueous liquid (A), which amounted to 6.5 litreg, was repeatedlyextracted with ether, and the ethereal extracts united, after which aquantity of a colourless, sparingly soluble substance which accompaniedthem was separated by filtration.This substance was almost insoluble in all the ordinary solvents,and appears to have been contained in the aqueous liquid in acolloidal form.It was, however, readily soluble in hot pyridine, fromwhich it crystallised in glistening plates, melting and decomposing at285-290O. The quantity so obtained was 0.9 gram :0.1253 gave 0.3310 CO, and 0,1192 H20.C,,H,,O, requires C = 72.1 ; H = 10.4 per cent.This substance, when dissolved in chloroform with a little aceticanhydride, gave on the addition of a few drops of concentratedsulphuric acid a series of colour reactions similar to those produced byipuranol, C23H380,(0H)2 (Trans., 1909, 95, 249), and it appears,in fact, to be a lower homologue of the latter.A s it does not agreein its properties with any substance of the above formula which hashitherto been described, it is proposed to designate it citrutlol, withreference to the generic name of the plant from which it has beenobtained .It was ascertained that citrullol exhibits no physiological activitywhen administered to a dog in doses of 0.05 gram.Diacetylcitrullol, Cz2H3,0,( CO-CH,),.-This was obtained by heatingcitrullol with acetic anhydride, from which it separated i n glisteningneedles, melting at 167" :C = 72.0 ; H = 10.6.0.1330 gave 0.3378 CO, and 0.1098 H,O. C = 69.3 ; H= 9.2.C26H4206 requires C = 69.3 ; €€ = 9.3 per cent.The ethereal liquid from which the citrullol had been separated byfiltration, as above described, was subsequently evaporated, but ityielded only a resinous product from which nothing definite could beisolatedPOWER AND MOORE: THE COSSTITUENTS OF COLOCYNTH.103Isolation of an Alhloidal Principle.The aqueous liquid, which had previously been extracted with ether,was treated with a solution of basic lead acetate. This produced avoluminous, yellow precipitate, which was collected, washed, and thensuspended in water and decomposed by hydrogen sulphide. Onfiltering the mixture a liquid was obtained which, after acidifying withhydrochloric acid, responded to the ordinary alkaloid reagents. It wasrendered alkaline by means of ammonia, and extracted many timeswith chloroform. The chloroform extracts were united and repeatedlyshaken with dilute (10 per cent.) hydrochloric acid.The acid liquidswere at once brought into a solution of ammonia, and the precipitatedbase extracted by means of chloroform. On the evaporation of thesolvent there was obtained a small amount (about 5 gramsj of a lightbrown product, which was resinous in character, very weakly basic,and possessed an extremely bitter taste. It dissolved sparinglyin dilute acids, and was precipitated from its solutions by the usualalkaloid reagents, including tannin. Neither the free base nor itssalts could be obtained in a crystalline condition. On warming thebase with alkali hydroxides it dissolved, and, on prolonged boiling,ammonia was evolved.When heated with 20 per cent. hydrochloricacid it yieIded ammonia and pyridine, the latter having been identifiedby its odour, and by the formation of its platinochloride.The basic principle was not glucosidic, as no sugar was formed onboiling its acid solutions. It represents one of the physiologicallyactive constituents of colocynth, as doses of 0.1 gram administered todogs produced very drastic purgation.The filtrate from the above-mentioned basic lead acetate precipitatewas treited with hydrogen sulphide for the removal of the excess oflead, and the filtered liquid concentrated under diminished pressure toa small volume. It was then treated with a large volume of strongalcohol, which effected the precipitation of a quantity of inorganicsalts, consisting chiefly of the chloride, sulphate, and nitrate OFpotassium, togsther with a little sugar.The latter yielded d-phenyl-glucosazone, melting at 208--310°. The clear alcoholic liquid wasdecanted from the precipitated material, mixed with purified sawdust,and the thoroughly dried mixture extracted in a Soxhlet apparatuswith chloroform. This removed a small quantity of a brown syrup,whicb, on hydrolysis, yielded a sugar which readily reduced Fehling’ssolution, and from which d-phenylglucosazone, melting at 208-2 loo,was prepared, It is therefore evident that the aqueous liquid con-tained a very small amount of a glucosidic substance, but this coul104 POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH.not be obtained in a form which would permit of its being moredefinitely characterised.Examination of the Resin (B).Isolation of a-Elaterirt.This resin was a brown solid, which softened below loo', andamounted to 675 grams.It was digested with about 2 litres of strongaloohol, in which i t only partly dissolved. The undissolved portionwas collected, washed first with alcohol, and then with ether, when itwas obtained in small, colourless crystals, melting and decomposing at227-230'. On recrystallising this product from alcohol, it formedsmall, glistening, hexagonal prisms, melting and decomposing at 232O!rhe amount of crystalline substance thus obtained was 80 grams,corresponding with about 1.08 per oent.of the weight of colocynthpulp employed :0.1446 gave 0.3655 CO, and 0.1060 H,O. C = 68.9 ; H - 8.1,@20H2805 requires C = 68.9 ; H = 8-0 per cent.C,,H,*O, ,, C=68*9 ; H=84 ,, ,,Ca8H,,07 ,, C=69*1 ; H=7*8 ,, ,,This substanoe a,grees in crystalline form, melting point, and solu-bility, and in all its chemical properties with a-elaterin, as previouslydescribed by us (Trans., 1909, 96, 1989). Its empirical formulacannot yet be considered definitely established.A determination of its speoific rotatory power gave the followingresult :0.3121, made up to 20 C.C. with chloroform, gave a , - 2'9' in a %durn.tube, whence [a], - 68.9'.The alcoholic solution of the resin (B), from which the a-elsterinhad been separated by filtration as above described, together with thealcoholic and ethereal washings from the latter, was mixed with puri-fied sawdust, the thoroughly dried mixture being then suocessivelyextracted in a Soxhlet apparatus with light petroleum (b.p. 35-509),ether, chloroform, ethyl acetate, and alcohol.Petroleum Extract of the Resin (B),Isohtion of Hentriacontane, C31H64, and a Phytostevol, C,7H,60,This extract was a dark green, waxy solid, and amounted to34 grams. It was dissolved in ether, the ethereal solution beingsuccessively shaken with dilute aqueous sodium carbonate and sodiumhydroxide, which, however, removed nothing. The ether was accord-ingly evaporated, and the residue hydrolysed by boiling with aPOWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH. 105alcoholiu solution of potassium hydroxide, after which the alcohol wasremoved, water added, and the alkaline solution of potassium saltsextracted with ether.The ethereal liquid was mashed, dried, and thesolvent removed, when a small quantity of a crystalline product wasobtained. This was dissolved in 250 C.C. of absolute alcohol, and thesolution kept for some hours, when a small quantity of an almostcolourless substance separated, This was collected and washed withcold alcohol, after which i t was distilled under diminished pressure.The distillate, which rapidly solidified, was crystallised from ethylaoetate, when small, glistening, colourless leaflets, melting a t 68O,were obtained :0,1344 gave 0.4176 CO, and 0.1824 H,O.The substance was thus identified as hentriacontane.The alcoholic solution from which the hntriacontane had beenremoved by filtration was concentrated to a small volume and dilutedwith water, when a quantity of a crystalline substance separated.This was collected and washed with a little ethyl acetate, after whichit was distilled under diminished pressure.The distillate was crystal-lised from a mixture of dilute alcohol and ethyl acetate, when i tformed colourless, glistening leaflets, melting at 160-1 62'. Theamount of substance so obtained was 1.3 grams :C = 84.7 ; H = 15.0.C,,H6, requires C = S5.3 ; H = 14.7 per cent.02205, heated at 115', lost 0.0104 H,O.071493 gave 0.4560 CO, and 0.1590 H20.H,O = 4.7.C27H,,0,H,0 requires H,O = 4.5 per cent.C,7H,,0 requires C = 83.9 ; H = 11.9 per cent.C=83.3 ; H= 11.8.This substance thus agrees in composition with a phytosterol, andit yielded the colour reactions of this class of compounds.It wasfound to be optically inactive, and in this respect appears to differfrom any of the phytosterols which have hitherto been recorded,The acetyl derivative, when crystallised from acetic anhydride,separated in glistening plates, melting a t 175-177'.Examination of ths Ratty Acids.The aqueous, alkaline solution of potassium salts, from which thehentriacontane and phytosterol had been removed by extraction withether, was acidified and again extracted with ether. The etherealsolution was washed, dried, and the solvent removed, when a quantity(12 grams) of fatty acids was obtained which, when distilled underdiminished pressure, passed over between 220' and 250°/15 mm.Tengrams of the mixed acids were converted into their lead salts, andthe latter digested with ether, when the greater portion dissolved.Both the soluble and insoluble portions were decomposed by hydro106 POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH.chloric acid, and the regenerated fatty acids purified by distillationunder diminished pressure. The soluble portion of the lead saltsyielded 8 grams of liquid acids, whilst the insoluble portion gave 1.5grams of solid acids.The Liquid Acids.-These acids, when distilled under diminishedpressure, passed over between 225O and 235'/15 mm. An analysis anda determination of the iodine value gave the following results :0.1406 gave 0.3964 CO, and 0.1460 H,O.0.5625 absorbed 0.8346 iodine.C = 76.9 ; H = 11.5.Iodine value = 148.4.C,,H,,O, requires C = 76.6 ; H = 12.1 pet cent.ClSHs2O2 ,, C = 77.1 ; H = 114 ,, ,, Iodine value = 181.4.I n order to obtain more definite information respecting the natureof the above mixture, a quantity of it was oxidised according to thomethod described by Lewkowitsch (Chemical Technology and Analysisof Oils, Pats, amd Wax68, 1904, Vol.I., p. 360). This resulted inthe formation of dihydroxystearic acid (m. p. 125-127') and tetra-bydroxystearic acid (m. p. 157-1 60"), the latter in predominatingamount.It may thus be concluded that the liquid acids consisted chiefly of amixture of oleic and linolic acids, the latter predominating.The Solid Acids.-These acids melted at 56-5S0, and, on analysis,gave the following result :0,1430 gave 0.3955 CO, and 0-1636 H,O.Iodine value = 90.1.C = 76.4 ; H = 12.7.C,,H,,O, requires C = 75.0 ; H = 12.5 per cent.C18H3602 ,, C= 76.1 ; H= 12.7 ,) 1,By repeated crystallisation from acetic acid a small amount of anacid melting at 68-69O was obtained, from which a silver salt wasprepared and analysed :0.21 18 gave 0.0576 Ag.From the above results it is evident that the solid acids consisted ofAg = 27.2.C18H,50,Ag requires Ag = 27.6 per cent.a mixture of palmitic and stearic acids.Ether and Chloroform Extracts of the Besin (B).Theywere light-coloured resins, and, with the exception of about 10 gramsof a-elaterin and a little of the previously-mentioned citrullol, nothingdefinite could be isolated from them.When heated with a solution ofsulphuric acid iri dilute alcohol they yielded no sugar, and thereforecontained nothing glucosidic.Both of the above-mentioned extracts were found to possesa avery marked cathartic action, which was doubtless due in part toThese extracts amounted to 169 and 180 grams respectivelyPOWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH. 107the presence of small quantities of the previously described alkaloidalprinciple, as about 3 grams of the latter were obtained from them.The activity of the extracts was, however, not appreciably diminishedby the complete removal of the alkaloidal principle, as they thenproduced drastic purgation when administered to dogs in doses of 0.1gram.Ethyl Acetate and Alcohol Extracts of the Resin (B).These extracts were brown resins, amounting to 85 and 100 gramsThey respectively, and nothing definite could be isolated from them.were not glucosidic, and possessed no purgative action.Examination o f Colocynth Seeds.The material required for the proceeding investigation of the pidp ofcolocynth fruit having rendered available a large quantity of the seeds,it appeared desirable to examine the latter with respect to their moreimportant constituents.A small portion (10 grams) of the crushed seed was tested for thepresence of an alkaloid by treatment with Prollius's fluid, when distinctreactions were obtained with the usual reagente. These reactionswere probably due to the presence of a very small amount of thesame alkaloidal principle as that contained in the pulp of the fruit.Separation of an Enzyme.A quantity (2 kilograms) of the crushed Eeed was extracted bypercolation with cold light petroleum for the removal of the fattyoil, after which the material mas mixed with cold water and themixture kept for several hours.The aqueous liquid was thenexpressed and filtered, and to it a quantity of strong alcohol wasadded. A voluminous, light-coloured precipitate was thus produced,which was collected, washed with a little alcohol, and dried in adesiccator. The product so obtained amounted to 10 grams, and,although containing a large proportion of inorganic material, i treadily hydrolysed P-glucoaides.The Fatty Oil.The amount of fatty oil contained in the seed, a8 determined by theextraction of 50 grams of the ground material in a Soxhlet apparatuswith light petroleum (b.p. 35-50°), was 12.72 per cent.The oil obtained was a clear pale yellow liquid, which was devoidof optical activity. A determination of its constants gave thefollowing results : specific gravity, 2Oo/2O0= 0*92i3 ; acid value, 2.6 jeaponification value, '186.7 ; iodine value, 126.6108 POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH.Hydrolysis of the patty Oil. holation of c6 Php?OSteTOE, C20H340.A quantity (150 grams) of the oil was hydrolysed by boiling withalcoholic potassium hydroxide, the alcohol removed, water added, andthe alkaline solution of potassium salts extracted with ether.Theethereal liquid was washed, dried, and the solvent removed, when asmall quantity of a crystalline substance was obtained. This wasdistilled under diminished pressure, after which it was crystallisedfrom a mixture of dilute alcohol and ethyl acetate, when i t separatedin colourless, glistening plates, melting at 158--160'. The amountof substance so obtained was 0.3 gram :0.1700 gave 0,5154 CO, and 0.1784 H,O. C=82*7 ; H= 11.3.This substance was evidently a phytosterol, and it yielded theA determination of its0.2473, made up to 20 C.C. with chloroform, gave aD +Oo12' in aThe acetyl derivative, when crystallised from acetic anhydride,C,,H,,O requires C = 52.8 ; H = 11.7 per 1 ent.colour reactions of this class of compounds.specific rotatory power gave the following result :2-dcm.tube, whence La],, + 8.1'.separated in glistening plates, melting a t 167-1 70".The Fatty Acids.The alkaline solution of potassium salts, which had been extractedwith ether as above described, was acidified and again extracted withether, the ethereal solution being washed, dried, and the solventremoved. The fatty acids thus obtained amounted to 87 per cent. ofthe weight of the oil. When distilled under diminished pressure,they passed over between 240' and 245'/15 mm. as a viscous liquid,which solidified on cooling to a soft, nearly colourless mass. Adetermination of the constants of the total acids gave the followingresults :Melting point (complete fusion), 29.5-32' ; specific gravity,5Oo/5O0 = 0.8910 ; neutralisation value, 195.6 ; iodine value 13 1.1.These constants, both for the fatry oil and the total acids obtainedtherefrom, are in fairly close agreement with those recently recordedby Grimaldi and Prussia (Chern.Zeit., 1909, 33, 1239). The last-mentioned investigators had, however, extracted the colocynth seedsby means of carbon tetrachloride, and describe the oil as having areddish-yellow colour with a slight green fluorescence.Summary.The results of the preceding investigation may be summarised asfollows POWER AND MOORE: THE CONSTITUENTS OF COLOCYNTH. 109The material employed consisted of the dried, peeled fruit ofCitrullus Colocynthis, Schrader. The pulp of the fruit, deprived ofits seeds, represented 24.4 per cent.of the whole.On extracting the pulp with alcohol, and subjecting the resultingextract to distillation with steam, a very small amount of a paleyellow essential oil was obtained, From the portion of the extractwhich mas soluble in water, the following substances were isolated :(i) A new dihydric alcohol, C22H3602(OH)Z (m. p. 285-290°),designated as citrullol, which is apparently a lower homologue ofipuranol, and yields a diacetyl derivative melting at 16'7'. (ii) Anamorphous, alkaloidal principle, which is a very weak base, and fromwhich no crystalline derivative could be prepared; it possesses anextremely bitter taste, and represents one of the purgative principlesof the fruit.The aqueous liquid from which the above-mentionedsubstances were isolated contained, furthermore, a quantity of in-organic salts, a Iittle sugar, and a very small amount of an amorphous,glucosidic substance.The portion of the alcoholic extract which was insoluble in waterconsisted chiefly of resinous material, from which, however, a quantityof a-elaterin (m. p. 232'; [a],- 68.9') was isolated (compare Trans.,1909, 95, 1989). After the separation of the latter substance,the resin was extracted with various solvents, when it yielded a smallamount of hentriacontane, C31H,, (m. p. 68') ; a phytosterol, C,7H,,0(m. p. 160-162', optically inactive) ; a mixture of fatty acids, and afurther quantity of a-elaterin, together with a little of the above-described alkaloidal principle, None of the extracts from the resinwere glucosidic.The ether and chloroform extracts possessed markedpurgative properties, even after the complete removal of the activealkaloidal principle.The seeds of the colocynth, which represented '75.5 per cent. of theentire peeled fruit, were found to contain traces of an alkaloidalprinciple, a small amount of an enzyme which hydrolyses /3-glucosides,and a quantity of fatty oil corresponding to 12-72 per cent. of theweight of the seed. The constants of the fatty oil, and of the totalfatty acids obtained therefrom, were determined, and from the oil asmall amount of a phytosterol, C?oH340, was isolated, which melted atl58-l6O0, and had [.ID + 8-19The results of the present research have established the fact thatthe so-called '' colocynthin " and '' colocynthitin," as well as theother products obtained from colocynth by previous investigators t owhich specific names have been attached, consisted of mixtures of avery indefinite character, and that the amount of glucosidic substancecontained in the fruit is extremely small. On the other hand, it hasnow been ascertained that the purgative action of colocynth is due t110 QORTNER: A CONTRIBUTION TO TEEat least two principles, one of which is alkaloidal, although a veryweak base, and apparently incapable of forming any crystalline salts,whilst the other source of activity is represented by some non-basicprinciple or principles contained in both the ether and chloroformextracts of the resin, All the attempts to obtain the last-mentionedactive principle in a more definite form were, however, unsuccessful.No evidence could be obtained of the presence in colocynth ofp-elaterin, which constitutes the physiologically active constituent o€the f r u i t of EcbaZZiunz EZateriunz.I n conclusion, the authors desire to express their best thanks t oDr. H. H. Dale, Director of the Wellcome Physiological ResearchLaboratories, for having kindly conducted the numerous physiologicaltests involved in this investigation.THE WELLCONE CHEMICAL RESEARCH LABOXATORIES,LONDON, E.C