vous matter in the interior, but in being of a homogeneous structure. They are also pale, transparent, and of a slightly reddish tint, and have their surface studded, here and there, with small bodies of a round or oval form. "STRUCTURE OF THE GANGLIA. They are of a reddish-gray colour, and composed of two coats or tunics, in the interior of which are found globules, nervous fibres, and blood-vessels. "The Tunics are distinguished into an external, composed of condensed cellular tissue, and an internal, more delicate than the preceding, which sends off processes from its inner surface into the substance of the ganglion. "The Globules are small bodies, nearly spherical in form, and having caudal or tail-like processes. Delicate fibres extend between them and connect them. The greater number of anatomists consider them identical with the cineritious substance of the cerebro-spinal axis. "The Nervous Fibres found in the ganglia may be arranged into the sensific, motific, and organic. The arrangement of these in the ganglia is most intricate, and is consequently made out with much difficulty. The sensific and motific fibres, which have been already mentioned to be derived from the cerebro-spinal axis, and which, in the ganglionic nerves, run parallel to, and are in apposition with one another, in the ganglia separate from each other, repeatedly unite and again separate, and thus form a most complicated net-work or plexus, the intervals of which are occupied chiefly by the globules. With the exception, then, of their separation, the sensific and motific fibres undergo no change in the ganglia ; they are not increased in size in passing through them, and they have no further connexion with the globules than merely running between them. The organic fibres on the other hand, are said to commence in the ganglia, in which they arise from the caudal processes of the globules; when such fibres then traverse the ganglia, they are frequently increased in size by the addition of new fibres derived from the globules." P. 804. We regret that our space does not enable us to insert the excellent remarks of Dr. Lizars on the functions of the ganglionic system; " they are, however, well worthy of perusal. The work is brought to a conclusion by a description of the reproductive organs, in which the latest researches are introduced. Those of our readers who are acquainted with the writings of Baer, Purkinje, W. Jones, R. Wagner, Barry, and others, will recognise the accuracy of the subjoined account of the mammiferous ovarium ovum : "THE OVA, Ovula, or vesicles of Baer, by all of which names they are known, are the germs from which the embryo or offspring are produced. It has been said that they are suspended in the Graafian vesicles by retinacula; in the smaller vesicles they are placed nearly in the centre, but in those which are fully formed, they are situated close to the inner surface or epithelium. Each is of a spherical shape, is about of a line, and presents the following parts: First, the exterior is covered with a dense layer of granules, which form what is termed the tunica granulosa; these granules are similar to those contained in the fluid of the Graafian vesicle, and those which enter into the formation of the membrana granulosa of that body, and the retinacula. Secondly, within the tunica granulosa is another thick tunic, named the zona pellucida; it is composed of an albuminous mass, enclosed in a membrane of extreme tenuity; it is transparent, and when seen under the microscope exhibits the appearance of a bright ring. Thirdly, contained in the zona pellucida is a mass termed the yolk, consisting of granules or cells and fat globules. Fourthly, lodged at first in the middle, but afterwards on one side of the yolk, is a minute body, to which the name of germinal vesicle, or germinal vesicle of Purkinje, has been given; its diameter is about th of a line; and its contents are transparent, except at one point. Fifthly, and lastly, within the germinal vesicle and close to its surface, is an opaque spot, whose diameter is only about or of a line: this is termed the germinal spot, or germinal spot of Wagner. The germinal vesicle and spot form the essential parts of the ovum; it is at the latter that the development of the embryo commences. These parts of the ovum will be impressed upon the memory by arranging them in a tabular form." P. 895. The extracts we have given will enable our readers to judge of the general scope and execution of the "Text-Book," which we can with much satisfaction recommend to those for whose assistance it is more especially designed, feeling assured that the student will here find, in addition to the ordinary contents of works of this class, a large number of important facts relating to the higher branches of anatomical science. I. THE PHARMACOPIA OF THE ROYAL COLLEGE OF PHYSICIANS II. A DISPENSATORY, OR, COMMENTARY ON THE PHARMACOPEIAS III. THE LONDON DISPENSATORY, &c., &c. By Anthony Todd Thomson, M.D., F.L.S., Professor of Materia Medica, Therapeutics, and Medical Jurisprudence in University College, London, Fellow of the Royal College of Physicians in London, &c., &c. 8vo. pp. 1317. London, 1844. [Continued from page 219.] WITHOUT further preface we continue our examination of the Edinburgh Pharmacopoeia, and of Dr. Christison's and Dr. Thomson's Dispensatories. Ferri Sulphuretum.-The following are the directions of the Edinburgh College for preparing this compound :— "FERRI SULphuretum. The best Sulphuret of Iron is made by heating an iron rod to a full-white heat in a forge, and rubbing it with a roll of sulphur over a deep vessel filled with water to receive the fused globules of sulphuret which form. An inferior sort, good enough however for Pharmaceutic purposes, is obtained by heating one part of sublimed sulphur and three of iron-filings in a crucible in a common fire till the mixture begins to glow, and then removing the crucible and covering it, until the action, which at first increases considerably, shall come to an end." The process of the Dublin Pharmacopoeia, is as follows: "Let an iron rod be heated to whiteness in a very strong fire, urged by bellows, and being immediately removed from the fire, let it be applied to a solid mass of sulphur. Let the Sulphuret of iron received in water be separated from the Sulphur, then dried and kept in close vessels." These processes are mixed and metamorphosed by Dr. Christison in the following manner :— "FERRI SULPHURETUM, E. D. Protosulphuret of Iron Sulphuret of Iron. PROCESS, Edin. Dub. A purer sulphuret may be obtained by heating an iron rod to a white heat in a blacksmith's forge, applying a stick of sulphur to the end of the rod, and collecting in water the fused globules which fall down. These should be freed of sulphur and kept in a close vessel." Mix them thoroughly; heat the mixture in a covered crucible till it become red hot; remove the crucible from the fire and allow the action to go on without heat. Dr. Christison observes, that the Sulphuret which is prepared from ironfilings by one of the Edinburgh processes, contains an excess of iron ; this excess is indeed so obviously great that it is singular it should have been directed to be employed. Protosulphuret of iron consists of one equiv. of sulphur 16+ one equiv. of iron 28, and supposing no sulphur to be sublimed or burnt in the operation, the result of it must consist of 44 parts of sulphuret and 20 of iron; so that when 16 of sulphur are heated with 48 of iron, the mass must consist of 44 parts of sulphuret mixed with 20 parts of iron; and when 64 grains are acted upon by dilute sulphuric acid, the gas obtained is a mixture of about 46 cubic inches of sulphuretted hydrogen, and 33 cubic inches of mere hydrogen. It is indeed true that the hydrogen does no absolute mischief, but the escape of this gas, especially when mixed with sulphuretted hydrogen, is always disagreeable; added to which, about four-tenths of the sulphuric acid employed in liberating this mixture of gases is wasted. Dr. Thomson has entirely omitted the Dublin process; with respect to the Edinburgh formulas, he says, "the result of the first contains an excess of iron it is only by the first process, carefully executed, that a pure sulphuret is obtained." We need hardly observe that the remark should have been, that the result of the first process contains no excess of iron; it is the second which does so. Ferrugo is the preparation which we shall next notice. The directions for obtaining this substance, which we find in the index is translated Rust of Iron, is thus given in the Edinburgh Pharmacopoeia. "FERRUGO. Take of Sulphate of iron, four ounces: Sulphuric Acid (commercial) three fluidrachms and a-half. Stronger Aqua Ammonia three fluidounces and a-half. Water, two pints; Dissolve the Sulphate in the water, add the Sulphuric acid, and boil the solution; add then the Nitric acid in small portions, boiling the liquid for a minute or two after each addition, until it acquires a yellowish-brown colour and yields a precipitate of the same colour with ammonia. Filter; allow the liquid to cool; and add in a full stream the Aqua Ammoniæ, stirring the mixture briskly. Collect the precipitate on a calico-filter; wash it with water till the washings cease to precipitate with nitrate of baryta; squeeze out the water as much as possible; and dry the precipitate at a temperature not exceeding 180°. "When this preparation is kept as an antidote for poisoning with arsenic, it is preferable to preserve it in the moist state, after being simply squeezed." Dr. Christison, in his Dispensatory, has accidentally substituted three fluidounces and a-half of sulphuric acid for three fluidrachms and a-half. It will be remembered that, in preparing the Ferri oxidum nigrum, the protoxide of half of the sulphate of iron is converted into sesquioxide by means of nitric acid; and for this purpose, on that occasion, the College direct pure nitric acid of sp. gr. 15 to be employed, while in Ferrugo, they order commercial nitric acid of sp. gr. 1·380 to be used for a similar purpose; for this diversity of practice we can discover no reason; the commercial acid is the more economical, and why it should not have been used in both preparations we are at a loss to conjecture. We attempted to prepare this medicine in the mode ordered, adding the nitric acid a fluidrachm at a time to the solution of sulphate of iron, and heating it after each addition; we found, however, on employing the test recommended by the College, of the colour of the precipitate yielded by ammonia, that the whole of the protoxide of iron was not converted into sesquioxide until the boiling had been so long continued as that scarcely 16 fluidounces of Solution remained, consequently 24 fluidounces of water were evaporated; as the solution was evidently much too concentrated to be conveniently decomposed, water was added to it to make it up to two pints, or the original measure; on mixing ammonia with a small portion of this diluted solution in a test tube, so gelatinous a precipitate of sesquioxide of iron was formed, that on inverting the tube scarcely a drop of liquid left it. The quantity of the solution was then, by the addition of water, increased to four pints, and even then the precipitate given by the ammonia was so bulky, that scarcely two pints of clear liquor could be poured off from it, after allowing eighteen hours for the subsidence of the oxide of iron. It is, we think, quite evident, that if any one had attempted to prepare Ferrugo according to the directions of the Pharmacopoeia, they never would have found a place in it; as to the employment of the stronger instead of the weaker solution of ammonia, we refer to what we have said under the head of Ferri oxidum nigrum. There are some inconsistencies in the College directions for preparing the three precipitated oxides of iron, which we shall point out. Under Ferri oxidum nigrum the ammonia is to be "immediately" added in a full stream to the mixed and hot solutions of protoxide and peroxide of iron, whereas in Ferrugo the solution of iron, with evident propriety, is directed to be allowed to cool, before admixture with the ammonia. With respect to the Ferri Oxidum nigrum, the precipitate is directed to be washed, "till the water is scarcely precipitated by solution of nitrate of baryta ;" and the precipitated Ferri oxidum rubrum is to be washed "till the water is but little affected with solution of nitrate of baryta ;" whereas, Ferrugo is to be washed "till the washings cease to precipitate with nitrate of baryta." We need hardly say, that in our opinion, the directions in the last case are unreasonable, for we found that less than 10 drachms of Ferrugo required about four gallons of distilled water to effect the purpose directed. Dr. Thomson, like Dr. Christison, has given fluidounces of sulphuric acid in the formula for Ferrugo instead of fluidrachms, and we should suppose that the former had copied the error from the latter, had we not observed the proneness of Dr. Thomson to commit errors of this sort, as shown by his substituting fluidounces for fluidrachms of nitric acid in the formula for Ferri oxidum nigrum. The directing of fluidounces intead of fluidrachms of sulphuric acid in Ferrugo is not however the only grave error which Dr. Thomson has committed in this formula, for he has entirely omitted the nitric acid, so essential to the process; so that we have eight times the proper quantity of one acid directed to be used, and, as if by way of compensation, the whole quantity of another is omitted. Alluding to this preparation, Dr. Thomson says, "the salt thus formed has a yellowish-brown colour," meaning, we presume, the oxide thus formed; and he further states, "its composition, most probably, when properly prepared, is one part of sesquioxide of iron =80+2 parts of water 18, making the equiv. 98 (Fe2. 05. + 2 H. O.)" Now, how "one part" can be considered as 80, or "two parts" as = 18, we are at a loss to conjecture, and therefore propose to read one equivalent for one part, and two equivalents for two parts; in the formula, 05 is misstated for O3. Ferri Sulphas.-The Edinburgh formula for this salt is entirely left out of Dr. Christison's Dispensatory; it is as follows in the Pharmacopoeia :"FERRI SULPHAS. If the Sulphate of iron of commerce be not in transparent green crystals, without efflorescence, dissolve it in its own weight of boiling water acidulated with a little sulphuric acid; filter; and set the solution aside to crystallize. Preserve the crystals in well-closed bottles." Supposing commercial sulphate of iron to contain, as it usually does, some sesquipersulphate, it would dissolve in water, and any subsalt of the peroxide would be dissolved by the sulphuric acid; this process seems therefore calculated to reproduce the impurity which it is intended to remove; whereas, by adding a little iron, the sesquioxide would be reduced to protoxide, and any copper which the commercial salt might contain would be precipitated by it. Among the "formulas for ascertaining the requisite purity of the more important articles, and their freedom from known adulterations," we find with respect to sulphate of iron, the following in Dr. Christison's Dispensatory:"TESTS. Edin. Entirely soluble: its solution precipitated by excess of ammonia, yields on filtration a fluid which is colourless, or very pale blue." The reader will perhaps scarcely believe that not one word of this statement of the tests is to be found in the Edinburgh Pharmacopoeia, yet such is the case, for the tests which it gives are merely the following:- Pale |