XIII. On Organic Polarity.

By H. F. BAXTER, Esq. M.R.C.S.L. cated by C. LESTOURGEON, M.A., F.C.P.S.

Communi

[Read March 8, 1858.]

THE title that has been chosen, viz. "Organic Polarity," as the subject of the present communication may render it necessary to make a few preliminary observations on the object I have in view.

The subject treated of embraces that commonly included under the name of "Animal Electricity," or, more correctly speaking, that of " Electro-Physiology." The confused notions associated under the former head, and the absurdities that have been advanced in regard to Animal Magnetism and Mesmerism, together with other equally ridiculous opinions, may, in a great measure, account for the strong prejudices that are entertained towards investigations such as form the subject of the present paper, and this alone would form one strong ground for discarding the employment of that title, viz. that of Animal Electricity. But the title that has been selected, will be found, it is believed, to be the most appropriate; for it will be shewn in the sequel, that I have to treat of polar actions; that organic actions are accompanied with the manifestation of current electricity, and are therefore polar in their nature; and, consequently, it is upon this ground that it may be inferred that organic force is a polar force. Hence ORGANIC POLARITY will form the subject of the present communication.

ON THE MANIFESTATION OF CURRENT FORCE DURING THE ORGANIC PROCESS OF SECRETION IN THE LIVING OR RECENTLY-KILLED ANIMAL.

After Davy's celebrated discovery, in 1806, of the decomposition of the alkaline salts by voltaic electricity, and when he had established the important fact that acids were evolved at one pole and alkalies at the other pole of the battery (from whence arose the phrase polar decomposition), WOLLASTON immediately seized upon the idea that the animal secretions were effected by the agency of a power similar to that of a voltaic circle, and in the paper* containing this remarkable conjecture, which was published in 1809, he also suggested that “the qualities of each secreted fluid may hereafter instruct us as to the species of electricity that prevails in each organ of the body;" that as the stomach and kidneys secreted an acid for example, whilst the liver secreted an alkaline compound, the two former might indicate a positive electric state or condition, and the latter a negative state or condition. PROUT† cautiously advanced a somewhat similar opinion, and says, "Admitting that the decomposition of the salt of the blood, & c is owing to the immediate agency of a modification of electricity, we have in the principal digestive organs a kind of galvanic apparatus, of which the mucous membrane of the stomach and intestinal canal, generally, may be considered as the acid or positive pole,

Philosophical Magazine, Vol. XXXIII. p. 488.

+ On Stomach and Urinary Diseases, 3rd. edit. p. xxv.

while the hepatic system may, on the same view, be considered as the alkaline or negative pole, He also quotes an experiment of MATTEUCCI as, in some degree, confirming his opinion.

DONNE, upon applying one of the electrodes of a galvanometer to the stomach and the other to the liver, obtained an effect upon the needle, and the result of this experiment was subsequently confirmed by MATTEUCCIT.

The suggestion thus thrown out, that the stomach and liver formed poles similar to those of a galvanic pile, having apparently received some confirmation from experimental evidence, it now became of some importance to trace out the circuit, the path of the current; and, if possible, the origin of the power, so as to complete the whole evidence necessary for the proof of the truth of the suggestion.

Reasoning upon these facts, and assuming that the stomach and liver did actually form the two poles similar to those of a galvanic circle, it was reasonable to suppose that the electric current would pass from the stomach to the liver by the blood in the portal vein. To ascertain the truth of this supposition I now inserted the two platinum extremities of the electrodes of a galvanometer into the portal vein, and as far apart as possible, in order to obtain the supposed diverted current; but no effect was observed. The electrodes were then inserted one into the portal vein, the other into the hepatic vein, still no effect.

POUILLET and MULLER §, it may be observed, had previously ascertained that no effect occurred when they inserted one electrode into an artery, and the other into a vein, of a living animal.

No evidence could be obtained from these experiments indicative of the path of the current; the galvanic circle was therefore not complete; and some of the essential conditions were evidently wanting.

Repeating the experiments of MATTEUCCI upon other animals than rabbits, the effects observed by MATTEUCCI were not always obtained; as these results will again come under consideration, they need not now detain us.

Pondering over these failures it soon became evident that more correct notions in regard to the origin of the power in the voltaic circle were requisite; the term current also, with its ordinary associations (of something flowing in one direction), was a source of great embarrassment, and it was thus found that a deeper insight into a knowledge of FARADAY'S || opinions in respect both to the origin of the power in the voltaic circle, and to that of current force in particular, viz. as AN AXIS OF POWER HAVING CONTRARY FORCES EXACTLY EQUAL IN AMOUNT IN CONTRARY DIRECTIONS, was absolutely essential. To enter upon these points, however, would far exceed the limits of this paper, and it is to the admirable memoirs of this distinguished individual that I must therefore refer for the requisite information¶.

• BECQUEREL, Traité de l'Électricité, Tom. 1. p. 327. + Ibid. Tom. IV. p. 300.

Journal de Physiologie, Tom. v. p. 5.

§ MULLER'S Physiology, translated by BALY, Vol. I.

p. 148. 2nd edit.

|| Experimental Researches in Electricity.

The title of the papers in the Transactions of the Royal Society was so worded as to imply the notion, that these investigations were undertaken for the purpose of applying some of the discoveries of FARADAY to Physiology. To avoid this meanVOL. X. PART I.

ing a note was appended to point out in what manner the word to apply was intended to be understood, viz. as shewing the necessity of a thorough acquaintance with FARADAY's views in regard to voltaic action and his definition of current force. No reason has as yet occurred to lead me to alter this opinion, but on the contrary; and whatever value may be assigned to Professor GROVE's views, as advanced in his Essay, On the Correlation of Physical Forces, I am still of opinion, without wishing to detract from the merits of the latter philosopher that the views of FARADAY are by far the most philosophic. 32

Dismissing the notion that the stomach and liver are related to each other in the same manner as the poles of a galvanic circle are mutually dependent, and with a more correct knowledge of the origin of the power in the galvanic circle derived from FARADAY's memoirs, the thought arose that it might be during the formation of the secretions where the changes were actually going on, that the evidence sought for could possibly be obtained. these surmises were correct will now be seen.

How far

SECT. I. On the Manifestation of Current Force during the formation of the Secretions in the mucous membrane of the alimentary canal, viz. the stomach and intestines.

As the mode of employing the galvanometer and of conducting the experiments, together with the precautions necessary to be observed, have already appeared in the Philosophical Transactions of the Royal Society* for the years 1848 and 1852, it will not be necessary to enter into a minute detail of these particulars. The results also of the experiments in the present paper need only be related, as it is my intention to enter more deeply into the theoretical part of the question than could have been prudently attempted on the former occasion; for the time has now arrived, when, considering the great development that has taken place in regard to electrical science in general, we may reasonably hope to be enabled by means of scientific discussion, combined with experimental observation, to reduce the mass of unconnected facts with which the science of Animal Electricity abounds within some more general laws.

Although experiments performed upon the living animal may be considered as affording more satisfactory results, nevertheless, as the results can be obtained, when sensibility is destroyed, the following mode may be adopted in preference to the use of chloroform.

Let a few drops of strong prussic acid be dropped on the nose, insensibility is thus quickly produced; or let the animal be pithed, and upon laying open the chest or abdomen the heart will be found to beat and the circulation to continue. Under these circumstances, if the platinum electrodes of a galvanometer are placed one in contact with the mucous surface of the small or large intestine, the other in contact with the blood in a vein from the same part, a deflection of the needle will be obtained indicating a current through the instrument, the electrode in contact with the blood being positive to the other in contact with the mucous surface. If the same experiment be repeated with the mucous membrane of the stomach, the effects may vary. If the stomach be empty, then the electrode in contact with the blood of the vein coming from the same part will also be positive, but if there be any food in the stomach and should it contain much acid, then the electrode in contact with its mucous surface will most probably indicate a positive state. Now these are the fundamental facts and the results, which are readily obtained with proper precautions, and may be thus stated: when the electrodes of a galvanometer are brought into contact one with the mucous surface of the intestine in a living or recently-killed animal, and the other with the venous blood from the same part, an effect occurs upon the needle indicating the secreted product and the venous blood to be in opposite electric states.

Philosophical Transactions, 1848 p. 243, 1852 p. 279.

The amount of deflection of the needle would vary according to the delicacy of the instrument employed; with an ordinary galvanometer, consisting of but few coils, the deflection was from 30 to 8° or 10o.

When the electrode, instead of being in contact with the venous blood, is in contact with the arterial blood, or the surface of the mesentery, the effects upon the needle are the same, as far as the direction of the current is concerned, but the amount of deflection may not be so great.

Let us now endeavour to explain these results according to known actions, such as the chemical reaction of two fluids upon each other, or to the heterogeneity of fluids, as it is sometimes called. If, for example, a glass cell be taken having a porous diaphragm in its middle, such as a piece of membrane, so as to divide it into two cells, and into one compartment we pour an acid solution, and into the other an alkaline solution, and then dip the platinum electrodes of a galvanometer into each of these cells, an effect upon the needle is produced indicating the electrode dipping in the acid solution to be positive to the other. These facts, which have been well worked out by BECQUEREL*, may be enunciated in the following proposition: during the reaction of two fluids upon each other, that which performs the part of an acid takes positive electricity, and that of an alkali, negative electricity.

In experiments upon animals, as just related, it was found that the electrode in contact with the venous blood was positive to the other, excepting when there was much acid in the stomach, and then the electrode in contact with the mucous surface of the stomach was positive to the other in contact with the blood. Now in order to explain these results, under the supposition that they arise from the chemical reactions of the fluids upon each other, it must be supposed that when the electrode in contact with the venous blood is positive to the other, that then the blood acts as an acid, and not only so, but combines with the substances or fluids in the intestines. When it is found, however, that the electrode in contact with the stomach is positive, then it may be supposed, and rightly so, that the results are due to the chemical reactions which occur in that organ between the acids and other fluids that are there found. But should we be justified in supposing that when the electrode in contact with the blood is positive to the other in the stomach, the stomach being empty or containing but little acid, that then the blood is acting as an acid? Here, as in the intestines, it would be necessary to assume that immediately after the separation of the secreted product (the acid) from the blood had taken place, that they then immediately recombined, and not only so, but that the blood, in direct opposition to the well-known fact of its alkaline characters, must be acid in order to account for the effects produced. It would, therefore, appear that no grounds exist for believing that the results obtained in the living animal can be considered as entirely dependent upon the mere reaction of the heterogeneous fluids upon each other, upon their combination for example; and with out stopping to adduce more arguments against this supposition, let us now proceed to com

• Loc. cit. Vol. 11. p. 77.

pare the results with another class of phenomena, viz. with those actions which take place in a voltaic circle where decomposition is effected.

It will be better to confine our attention to the actions which take place in the exciting cell of a voltaic circle where the power originates, and withdraw our minds for the present entirely from the changes which take place in the decomposing cell of the battery where polar decompositions are effected: the principal object being to ascertain whether, during the decomposition of a compound, or during the separation of an acid from an alkali, the same effects are produced upon the galvanometer as occurs during the combination of an acid with an alkali.

Let us take an elementary circle, zinc, platinum, and a dilute solution of muriate of soda, and consider the two metals as forming the terminations of the electrodes of the galvanometer, one of zinc and the other of platinum, instead of having two platinum electrodes as heretofore. When the electrodes are dipped into the solution, the actions which take place are the following: the muriate of soda is decomposed by the attraction of the zinc for the chlorine or muriatic acid, whilst the soda is evolved on the surface of the platinum; now under these circumstances the platinum electrode, in contact with the soda, is positive to the other, and, according to common phraseology, the direction of the current is in the same direction as the cation (the alkaline compound, the soda) is supposed to travel. Here then is a case of decomposition, a separation of an acid from an alkali, effected by chemical agency, and the electrode in contact with the alkali is positive to the other in contact with the acid; the effect being contrary to that observed during the combination of an acid with an alkali, as has been just shewn. Let us now compare the results which occur in the animal with those which take place in the voltaic circle. When the electrode is brought into contact with the venous blood, it is positive to the other in contact with the secreting surface of the intestine; if it be now supposed that the blood is alkaline, and there is every ground for so doing, the electrode in contact with the blood is exactly similar to that in contact with the alkali in the voltaic circle; but instead of the secreted product combining with the other electrode, as the acid does in the voltaic circle, it passes away. In the animal the current may be supposed to be dependent upon the decomposition-if I may so term it-of the arterial blood, being as it were separated into its two elements, the secreted product and venous blood, just as the muriate of soda is decomposed and separated into its two elements, muriatic acid and soda.

At present, it may be remarked, that no opinion as to the mode in which the secretions are effected is being given; I am only endeavouring to ascertain now what does occur, and to what class of phenomena these actions, those of secretion, bear the greatest resemblance. This subject will again come under our consideration.

Before proceeding to shew that in other organs there exists the same manifestation of current force during secretion, I cannot omit noticing the opinion that WOLLASTON entertained in regard to the question now under consideration, and shall therefore quote his own words: "At the time," says WOLLASTON*, "when Mr Davy first communicated to

me his

• Loc. cit.