amounting often to 15 or 20 per cent.; this mixture of cresol and phenol is commonly known in commerce as liquid carbolic acid; it is used almost solely for purposes of disinfection. Pure phenol is generally described in text books as crystallizing in long needles, which fuse at 35° C. and boil at 186° C.; the crystals are also stated to be very deliquescent, and but sparingly soluble in water when melted. This description is not a very accurate one, being, in fact, a description of an impure body. Pure phenol fuses at 41° to 42° C., and boils at 184°; the crystals are not deliquescent. Water dissolves 5 per cent. of phenol at 16° C., but at 100° it will dissolve an unlimited quantity. On the other hand, the melted crystals will dissolve 20 to 25 per cent. of water, and this prevents the crystallization of the phenol at ordinary temperatures. If, however, the mixture be exposed to a temperature of o° C., a hydrate of phenol separates in the crystalline form. From the fact that phenol was separated from tar oil by means of an alkaline solution, and especially from its appearing to form a compound with potassic hydrate, it was supposed to possess an acid character; on further investigation, however, it was found to possess none of the characteristics of an acid, and it forms no definite salts with bases (Calvert, Fournal of the Chemical Society, vol. viii., pp. 67 and 68.) On the other hand, in its chemical relationships, it exhibits the character of an alcohol, and it may be regarded as the hydrate of the hypothetical radicle phenyl C.H,, just as ordinary alcohol is the hydrate of ethyl C,H,. Phenol is thus the alcohol of benzine, the first member of the aromatic series of hydrocarbons, and the analogy between ordinary alcohol and phenol is clearly shown if we write the formulæ of the different members of the series as derived from the radicle, of which the parent hydrocarbon may be considered the hydride. For instance, taking the radicles phenyl and ethyl respectively, we have:

In the one case, the second member is the alcohol phenol, and in the other case, ordinary alcohol. There is, therefore, prima facie evidence that phenol may be an alcohol, merely from the fact that its composition, as determined by analysis, enables it to supply the place of the alcohol member in the phenyl series. But in the chemistry of carbon, where cases of isomerism and metamerism are so abundant, this fact is not sufficient, and it is necessary to seek for confirmatory evidence in the chemical behavior of the compound. This evidence is furnished by several reactions in which phenol behaves in a manner closely analogous to ethylic alcohol under similar conditions. When, for instance, phenol is

acted upon by potassium, hydrogen is given off and is replaced by the metal

2 C6H5OH+K2=2 C6 H¿ OK+H2.

In a similar manner when alcohol is acted upon by potassium the same interchange takes place—

2 C, H, OH+K2=2 C, H, OK+H2.

Again, when phenol is heated with sulphuric acid, half the hydrogen of the acid is replaced by phenyl—

Sulphophenic acid being produced; from this the sulphophenates or sulphocarbolates are formed by replacing the remainder of the hydrogen by the metal whose salt is required. These changes are closely paralleled by the corresponding reactions of ethylic alcohol, which, with sulphuric acid, produces sulphethylic acid—

H} =

SO1+C, H, OH CH2SO,+H2O.

Н

In 1865 Calvert examined the white crystalline product which is formed when phenol is mixed with a strong solution of caustic potash, and which was supposed to be a salt of carbolic acid. It was found that the crystals consisted only of phenol, with a little adhering alkali. There can be no doubt, therefore, that phenol belongs to the alcohols, and absolutely pure phenol may be appropriately called "absolute phenol." Of this the sample before you is prepared in the form of minute granular crystals which fuse at 41° C. and boil at 184°. The crystals have a faint fragrant odor, and having no tendency to liquefy on exposure, they will probably be found a convenient pharmaceutical preparation. Phenol is produced by the dry distillation of several organic bodies besides coal, viz., Salicylic acid, gum benzoin, resin of Xanthorrhea hastilis, quinic acid, and chromate of pelosine. The action in the case of salicylic acid is especially interesting, as the latter may also be produced from phenol by the action of carbonic anhydride and sodium. At present salicylic acid is being manufactured from this source; its composition is the same as that of carbonic acid in which one atom of hydrogen is replaced by the radicle phenyl

A large number of derivatives have been furnished by phenol, some of which are of considerable commercial importance, although they were not applied to industrial uses to any great extent until nearly twenty years after the discovery of phenol; in fact, this body has a commercial history similar to that of oxalic acid, benzol and many other organic

compounds which, after their first discovery, were known for some years as chemical curiosities only, until at length they were found to possess qualities which make them useful to mankind, and which render their manufacture a profitable enterprise. It is little over twenty years since phenol was first manufactured on a large scale, and at the present time the production in this country amounts to several hundred tons annually. A large proportion of this is consumed in manufacturing two colored derivatives of phenol which are employed as dyes. I allude to the picric and rosolic acids. When nitric acid is made to act upon phenol, three different nitro-derivatives may be produced by varying the conditions under which the action takes place. In all cases the action consists in the replacement of part of the hydrogen of the phenol by the group nitryl (NO3), and 1, 2 or 3 atoms of hydrogen may be so replaced, forming the mono-, di- and tri-nitrophenic acids respectively, thus:

All these derivatives possess distinctly acid properties and form definite crystallizable salts, but only the last of them is of commercial importance. Tri-nitrophenic or picric acid is formed when nitric acid and phenol are allowed to react upon one another, and the mixture is afterwards boiled with concentrated nitric acid. Pure picric acid crystallizes in pale yellow needles, which dissolve in about eighty times their weight of cold water, forming an intensely yellow solution.

Like many organic compounds which have had 3 atoms of hydrogen replaced by 3 atoms of NO2, such as gun cotton, or trinitronaphthalene, picric acid, and especially the picrates, are liable to undergo violent decomposition when heated, the picrates of the alkalies exploding with much violence. The most important application of picric acid is for dyeing silk or wool, to which it imparts a beautiful lemon-yellow shade; the acid merely requires to be dissolved in water with the addition of a little sulphuric acid, which is found to assist the process of dyeing. When a solution of picric acid is gently heated with cyanide of potassium, isopurpurate of potassium is produced; from this the ammonium salt can be obtained, which exactly resembles the dyeing material, murexid or purpurate of ammonium—

CH,N,O,+3CNK+3HO=CH_KNO+CO,+NH3+2KHO

The other colored product derived from phenol is rosolic acid, known in commerce as aurine or coralline. This substance is produced when phenol is heated with an alkali, together with certain metallic oxides, and also when sulphophenic acid is heated with oxalic acid to a temperature of 120° C.; the last method is the one employed on the manufacturing scale. When the action is complete, the excess of sulphophenic acid is washed out by repeatedly boiling with water, and the rosolic acid is finally melted, in order to remove the water which it has retained; on cooling, it assumes the condition of an amorphous mass with a beetlegreen lustre, in which form it is known as aurine, or yellow coralline of

commerce. In this state rosolic acid contains a quantity of unchanged phenol; when freed from this, it may be obtained in the crystalline form. Aurine is soluble in alkaline solutions and in alcohol; it is largely employed for dyeing silk and wool, to which it gives a bright orange color, often seen on sheepskin mats. When aurine is heated under pressure with ammonia solution to 150° C., a coloring matter is formed which produces a red shade, instead of the orange shade imparted by aurine; this substance is called red coralline. A blue coloring matter is obtained from aurine by heating together aurine, anilin and benzoic acid; this, at one time rather extensively used, is now supplanted by the anilin dyes.

We have now completed the list of coloring matters which are derived directly from phenol, and it will be admitted that the contributions of this body to the great magazine of tar-colors is by no means unimportant.

I now pass on to the consideration of some of the properties of cresylic acid, or cresol. The remarks already made in reference to the constitution of phenol will equally apply to cresol, this body being an alcohol and not an acid. Three isomeric modifications of cresol are known, which are distinguished as para-, meta- and ortho-cresol, and these stand in the same relation to toluene as phenol does to benzene.

Paracresol constitutes the greater portion of the crude cresol derived from coal-tar; it is very deliquescent, and its presence in commercial phenol causes the latter to liquify on exposure; its boiling point is about 200° C. Orthocresol is believed to exist in coal-tar; but it has also been obtained (as well as paracresol) by fusing potassium toluene-sulphate with potassium hydrate—

C,H,SO,K+KOH=(C,H,)OH+K2SO1;

its boiling point is about 189° C.

Metacresol has not been obtained from coal-tar; it is formed by the resolution of thymol into cresol and prophylene, by heating with phosphoric anhydride; its boiling point is 195° to 200°.

C10H1,O=C,H,O+C3H6.

The derivatives of cresol have not been so perfectly studied as those of phenol, partly on account of the difficulty of obtaining the different isomers in a pure state in large quantities. None of them have yet been applied to any useful purpose in the arts or manufactures, but cresol itself is employed even to a greater extent than phenol for purposes of disinfection. The antiseptic qualities of cresol and phenol have been carefully studied during the last ten or fifteen years, and a large amount of experience has been gained by their practical employment as disinfectants. These alcohols possess some property by virtue of which they are able immediately to arrest those changes in organic bodies which owe their origin to the development of protoplasmic life. This is not effected by

oxidation or other chemical change, as in the case of the permanganates, ozone, chlorine, etc., for there is reason to believe that the antiseptics themselves suffer no change. Both phenol and cresol will precipitate albumen and gelatine from their solutions, and it has been suggested that they may exert a similar power on the sarcode which forms the structure of the above named organisms; whatever be the method by which the effect is produced, the fact itself is sufficiently established. Almost every species of decay to which organic matter is liable may be prevented by the presence of a minute quantity of the tar antiseptics, and from their volatile character they may be made to operate on the atmosphere as well as on liquid and solid bodies. This antiseptic quality was very soon recognized by medical authorities, and it was found that the usual septic condition of suppurating wounds might be entirely prevented by employing a dressing in which a small quantity of phenol or cresol was introduced; the subject was thoroughly investigated by Dr. Lister, of Edinburgh, to whom we are chiefly indebted for the antiseptic method of treating wounds, and also for some of the very convenient forms in which the antiseptics are applied.

The question naturally arises, if these antiseptics are so certain in their action upon the vital germs which accompany decay, may they not be useful agents for internal administration in those diseases in which the morbid state of the blood is supposed to be owing to the propagation therein of poisonous germs. Of course it is impossible to administer either phenol or cresol in a pure state, and even a weak solution is found too irritating to the delicate mucous surfaces of the stomach, except in very small quantities, so that for some time the test could not be applied. Recently, however, it has been found that the salts of sulphocarbolic acid, which may be given in tolerably large doses, are decomposed in the system, the phenol being re-formed and set at liberty. By this method it is possible to administer phenol in such quantities as to produce cerebral symptoms, but I have not seen a sufficient number of reports as to its action to determine its success or otherwise. Numerous other applications of these antiseptics have been made, and are continually being made as their properties become more generally known. I will only allude to the preservation of gelatin size in hot weather, and of hides that are intended for tanning. Some years ago I had a thorough trial made of this method of preserving hides, in order to ascertain whether the antiseptic solution had any injurious effect on the after process of tanning. The trial was made at the tanyard of Mr. Beakbane, near Liverpool, and it was found that the hides were in no way injured by a two per cent. solution of the antiseptics, but after lying in a wet state during several weeks of warm weather, they afterwards behaved in the tan-pit exactly like fresh hides. In conclusion, I beg to draw your attention to a few zoological specimens, which were collected three years ago by my brother in India, and sent to England in a two per cent. solution of crude cresol. The state of preservation is complete.—London Pharm. Journal.

ARBUTIN IN KALMIA LATIFOLIA.-Mr. George W. Kennedy, in the January number of the American Fournal of Pharmacy, reports the existence of Arbutin in the mountain laurel.