The first column in the above tabular view, represents the scheme proposed by Bacon, and designated by him "A Bi-literal Alphabet;" a scheme-as he points out, “practicable in all things that are capable of two differences." The advantage of representing every letter by five tokens, is that it dispenses with the necessity of spacing the letters from each other.

The second column represents an alphabet shown and described in Rees' "Cyclopædia" as already referred to. In this alphabet the first nine letters follow exactly the notation of Bacon. After the interpolated letter J, (which takes the symbol for K,) the remainder of the alphabet from K to V inclusive, follows regularly the notation of Bacon-shifted two letters downward. The only symbols differing from Bacon's, are those for X, Y, and Z.

The third column gives the alphabet of Swaim above mentioned. The author has not been successful in arranging for his letters the simplest combinations of taps and scratches which might have been selected; having given to N, R, T, and w, five signals, and to X, six; while four of his signs are sufficient to represent 30 different characters. Moreover by adopting a numeral system of designation, he has been driven to the awkward and entirely unnecessary expedient of introducing spaces into letters in seventeen cases, or in two-thirds of the alphabet; that is in all letters following the ninth letter-I.

The fourth column gives the alphabet of Schilling, as represented in Vail's "ElectroMagnetic Telegraph:" (page 156.) The date of this is uncertain; involving as it does the question when Schilling first employed a single circuit and a single galvanometer in his telegraphic arrangement. Whether he or Gauss and Weber first devised this very important simplification is equally undetermined; though the presumption is in favor of Schilling having been the first to introduce the bi-signal alphabet into telegraphy. With a judicious distribution of the simplest signs to the most frequent letters, the average number of elementary signals need not exceed two and a half for every letter used, (or just one-half the number required by Bacon's alphabet,) in any lengthy communication. Steinheil, who was very imperfectly acquainted with Schilling's labors, appears to regard his system as imitated from that of Gauss and Weber.* The fifth column gives the alphabet of Gauss and Weber, as represented in Turnbull's "Electro-Magnetic Telegraph." In this alphabet C and K have the same symbol; as have also F and v.

The sixth column gives the alphabet of Steinheil as represented in Dub's Anwendung des Elektromagnetismus: Berlin, 1863: (2d ed. 1873, sec. v, page 343:) in Vail's Treatise; (page 182:) and in Turnbull's Treatise; (1853, page 97.) In this alphabet c and K have the same character; I and J have the same; and u and v have the same; the letters Q, X, and Y, being dispensed with. Steinheil remarks of its arrangement, "The alphabet I have chosen represents the letters that occur the oftenest in German, by the simplest signs"; a plan also adopted by Schilling and by Gauss.

The seventh column gives the original alphabet of Morse, as devised by him (or by his assistant—Mr. Vail) in 1838; and for the first time described in his application for a patent dated April 7, 1838. This is accordingly the alphabet presented in Morse's first patent, dated June 20, 1840. In this, he has given the same symbol to G and J; the same to I and Y; and the same to s and z. It must be borne in mind that down to the year 1838, Professor Morse had conceived only the naval system of signals by means of numbered words, and the method of recording such numbers by the alternating or continuous zig-zag mark, equivalent to the right and left deflections of Steinheil's register; and that not till some time in January of that year (1838), did he make the great advance of substituting the up and down movement of the armature recorder, for its transverse motion. He then for the first time made his telegraphic communi

#

Sturgeon's Annals of Electricity, etc. vol. iii, pp. 448, 450.

+ Second edition, 1853, p. 60.

New York Journal of Commerce, of September 7, 1837, and of January 29, 1838.

cations by means of an alphabet; and improving on his predecessors, devised this alphabet in its simplest form, of a rectilinear succession of dots and lines.

A few years later, the modification given in the eighth column was adopted;* being the code now in use in this country. This second alphabet of Morse retains but seven of the letters in his original alphabet; namely, E, H, K, L, N, P, and Q. The remaining symbols are changed in their application. Both of these alphabets present the anomaly of employing for the letter L the unique symbol, a dash of double length: a symbol whose combinations with dots might have been much more appropriately reserved for designating numerals. And they both also present the very awkward arrangement of introducing in five or six cases, a space in the middle of a letter. This occurred with B, C, D, F, G or J, and R, in the first alphabet, and remains with C, O, R, Y, and Z in the later alphabet. Whence it becomes difficult to distinguish between C and IE, between 0 and EE, between R and EI, between Y and II, and between z and SE; and if on the other hand the intra-literal space be made too brief, C or R may easily be mistaken for s, o for I, and Y or z for H.

The ninth and last column gives the alphabet adopted by the Vienna convention in October, 1851, for European languages; as represented in Prescott's larger treatise on Electricity and the Electric Telegraph, 1877: (page 480.) This alphabet avoids the obvious blunder in Morse's notation, and presents a homogeneous system. In this code eleven of the Morse letters are changed: C, F, L, and R, having been taken from Gerke's alphabet, o, and P, from Steinheil's, and J, Q, X, Y, and z, from other sources. Of the original "Morse alphabet” only four letters are retained, viz, E, H, K, and N. This European or "international" alphabet is however in a few of its symbols, better adapted to the German than to the English language. Accordingly in the Atlantic cable alphabet, the two letters м (11), and o (111), have been transposed; as in English the letter o occurs nearly three times as frequently as the letter M.

We thus perceive by what apparently small steps so simple a contrivance as an alphabetic notation, (scarcely demanding the exercise of invention,) has been successively modified and improved. But although the "Vienna" alphabet is now universally employed elsewhere, American operators have not yet had the intelligent courage to incur the temporary additional labor and inconvenience of change, for the permanent advantage of a more perfect system. †

*Represented in Vail's Treatise, 1845, p. 27; in Turnbull's Treatise, 1853, p. 73; in G. B. Prescot''s Hist. of Electric Telegraph, 1860, p. 89; and in F. L. Pope's Modern Practice of the Electric Telegraph, 4th ed. 1871, p. 101.

"It has been proposed to introduce the European alphabet in this country also; but although the advantages of such a reform would doubtless be numerous, yet it may perhaps be better to suffer some inconvenience from an acknowledged imperfection, than to attempt to remedy it by introducing a change that would for a time cause serious annoyance to the thousands of skillful operators now in the service." (Prescott's Electricity and the Electric Telegraph, 1877, chap. xxx, p. 431.)

THE EFFECT OF IRRITATION OF A POLARIZED NERVE—“PFLÜ

GER'S ELECTROTONUS."

BY B. F. LAUTENBACH, M. D., PH. D.,

First Assistant in the Laboratory of Physiology at Geneva.

HISTORICAL RÉSUMÉ.

This

Ritter observed, when he applied for a long time ( hour) a strong galvanic battery to a nerve, that there resulted a continual decrease in the movements of the finger and the arm on the silver (i. e., negative) side of the battery. In the same parts on the zinc (positive) side he observed a continual increase in the motor effects of the current. effect lasted for a short time after the experiment was discontinued. On carefully repeating this experiment, Ritter came to the result that the current developed by the battery inhibited the voluntary movements in the arm to which the negative electrode was applied, while the mobility of the other arm, to which the positive electrode was applied, was increased.

Du Bois Reymond+ attributed these results to diminution and augmentation of the irritability of the nerves caused by the constant current; the augmented excitability being produced by the passage of an ascending current, while the diminished excitability was caused by a descending current.

In 1828-30 Nobili‡ observed certain facts which bear more nearly on our present subject than those observed by either of the previous experimenters. This investigator found that frog preparations, which through accident had become tetanized, grow quiet when a current in a special, or possibly in any, direction, was passed through the nerve. In explanation, Nobili believed that the constant current places the nerve in such a state as to render impossible the receiving and conducting of the contraction-producing cause. Nobili, at the same time, recommended his discovery to physicians for the cure of tetanus.

Matteucci § made some experiments on this subject, but these resulted in but little that was not previously known. With the exception that he proved that the relief afforded in tetanus by a constant current is but

* Beiträge zur näheren Kenntniss des Galvanismus, etc., Jena, 1802, B. ii. Unters. über thierische Electrici tät, B. i, p. 367.

Analyse expér. et théor. des phén. phys. produits par l'électric. sur le grenouille, etc., Annales de chimie et phys., 1830, p. 91.

§ Essai sur les phén, électr. des animaux, Paris, 1840, 8, p. 29.

transitory and that currents travelling in both directions act paretically, his results were but confirmatory of those obtained by Nobili.

The first who really systematically investigated this subject was Valentin.* This investigator applied the constant electrodes to the ischiadicus, just at the entrance of this nerve into the gastrocnemius, while the irritating electrodes were applied at the point of exit of the nerve from the pelvis. Valentin found that when the constant current was passing through the nerve the irritating current gave a weaker contraction than when this was not the case, or, at times, none.

This author also showed that the same diminution in the effect of the irritating current occurred when this was placed between the constant current and the muscle. This latter result, however, was produced in the experiments of Valentin only when the current was ascending, and not when a descending current was employed.

Eckhardt confirmed the observations of Nobili and Valentin. He found that an electrical irritation can be made to lose its effect when between it and the muscle a constant current is made to pass through a given portion of the nerve. Not only did he find this to be true for electrical but also for mechanical and chemical irritants. This inhibitory effect was manifest when the polarizing or constant current was made to pass in either an ascending or a descending direction, provided that this current was of a certain strength (5-6 large Daniel elements). This author also confirmed the statement of Valentin that when the irritation (mechanical, chemical, or electrical) is applied to the nerve above the point where this is being polarized the effect is no longer so constant. In his first paper Eckhard made the statement, which he afterwards withdrew, that the "paretic" effect was most constant when an ascending polarizing current was used.

In a second paper‡ Eckhard irritated by means of an induced current, and measured the muscular contractions thereby produced by means of a Helmholtz myograph. His previous observations were confirmed. When the constant current was applied to the nerve above the irritation, ascending polarization only diminished the effect of the irritation, thus showing a diminished excitability of the nerve between the positive electrode and the muscle. When the descending current was employed a state of augmented excitability of the nerve was produced between the negative electrode and the muscle.

Pflüger, § whose experiments and "laws" will frequently be referred to in this paper, was the next investigator who devoted his atttention to this field of research. He made use of weak currents, while the pre*Lehrb. der Phys. des Menschen, B. ii, Abth. 2, p. 155.

+ Der galv. Strom als Hinderniss der Muskelzuckung. Zeitschr. für rat. Med., N. F., B. iii, p. 198.

Ueb. den Einfl. des const. galv. Stromes auf die Erregbark. der motor. Nerven, Beiträge zur Anat. und Phys., H. 1, 1855, p. 25.

Allgem. Centralzeit., 1856, Nov. 22, 1857. Unters. über die Phys. des Elektrotonus, Berlin, 1859.

ceding investigators always employed strong currents. This author found that the ascending polarizing current did not under all conditions produce a diminution in the excitability of the nerve. The following are the results of this investigator:

M.

P. C.

I. C.

N.

-C*

"I. When a constant descending current is passed through the sciatic nerve near the gastrocnemius, and a descending irritating current is applied immediately above this, I found the irritation to give a smaller contraction when the constant current was passing through the nerve than when this was not the case."

Under these circumstances the muscular contractions were increased during the passage of the current.

"II. The constant descending current passes through the nerve near the central end, a descending irritating current is applied to the nerve nearer the muscle. The irritations seem stronger when the constant current was absent."

M.

N.

I. C.

P. C.

-C.

The contractions produced by the irritation are stronger during the absence of the polarizing current.

"III. The constant ascending current passes through the nerve near the muscle, while the irritation was made at a more central portion. During the presence of the constant current the contractions are stronger than when it is absent."

"IV. The constant ascending current is applied to the nerve near the plexus, while the ascending irritating current is applied nearer the muscle. During the presence of the constant current the contractions are less strong than when this is removed."

Contractions less strong during the passage of the polarizing current. In conclusion Pflüger sets up the theory that the action of all irrita*In these diagrams, which are added by the author for the easier understanding of the views of Pflüger, M stands for the muscle, N for the nerve, and C for its central end; I. C. and P. C. stand for irritating and polarizing current. The arrows give the direction of the current.