Table of Contents
Significant Events of the 1800's:
- 1850: Herman Helmholtz establishes the speed of nerve conduction
- 1857: Louis Pasteur proves fermentation is caused by a living organism
- 1860: Abraham Lincoln is elected President of the United States
- 1877: Thomas Edison invents the phonograph
- 1884: Ilya Mechnikov promulgates "Theory of Phagocytosis"
- 1895: Guglielmo Marconi invents radio-telegraphy
- 1898: Pierre and Marie Curie discover radium and polonium
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Electromotive Properties of the Human Heart #1 
Put into a single sentence, I am going to describe how the heart of man can be shown to act as an electrical organ, and what we learn from such action. It is a well-known fact that every beat of the heart is accompanied by an electrical disturbance; the nature of this disturbance has, moreover, been studied and understood with the assistance of cold-blooded animals, and in this laboratory in particular an investigation was carried out to learn whether or no warm-blooded animals manifest similar electrical disturbances.
It occurred to me that it should be possible to get evidence of electrical action on man by connecting not the heart itself, which is obviously impossible, but parts of the surface of the body near the heart with a suitable instrument; having verified this supposition, the next step was to see whether or no the same evidence can be obtained by connecting the instrument with parts of the body at a distance from the heart, with the hands or feet. The answer was, as you will see, satisfactory.
The fact that each beat of the heart gives an electrical change, beginning at one end of the organ and ending at the other, proves that the contraction does not occur throughout the mass of the heart at one and the same instant of time; if the two points A and B rose and fell together, there would be no alteration of the index. The movements of the index show that there is a fall of A at the beginning of the contraction, and a fall of B at the end of the contraction.
Waller AD. Introductory Address on The Electromotive Properties of the Human Heart. Brit. Med J, 1888;2:751-754
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Electromotive Properties of the Human Heart #2 
Let us now apply our instrument to the heart. This, which seems rather a bold proposition, is really a very simple and easy matter. We need simply dip the two hands into two basins of water which are in connection with our indicator, when we shall see that the mercury beats up and down with the pulse. These movements of the mercury are due to the electrical changes which occur with every beat of the heart; or we may dip a hand and a foot each into a basin of water with a similar result, only it must be the right hand, the left will not do. This difference, apparently so curious and puzzling at first sight, which seemed unsymmetrical and irrational, is in reality most reasonable, and proved to be the master key which threw open the meaning of every subsequent experiment. The difference depends upon the unsymmetrical position of the human heart, which is tilted to the left side somewhat. Waller AD. Introductory Address on The Electromotive Properties of the Human Heart. Brit. Med J, 1888;2:751-754
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Electromotive Properties of the Human Heart #3
Demonstrating Waller's Dog "Jimmy"
The heart of a quadruped (dog, or cat, or rabbit, or horse) is placed far more symmetrically than in man; it is very nearly in the middle line, so that the changes of electrical level whose foci are at A and B spread straight up and down the body, not obliquely, as in man. The upper half of the body is under the influence emanating from B; the lower half under that emanating from A. Unlike what occurs in man, the two front paws coupled with an indicator are silent, while either front paw taken with either hind foot gives us the now familiar answer. Waller AD. Introductory Address on The Electromotive Properties of the Human Heart. Brit. Med J, 1888;2:751-754
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Human Complete Heartblock
Chauveau A. De La Dissociation Du Rythme Auriculaire et du Rythme Ventriculaire
Il n'est pas rare que la présence des ampoules introduites dans les cavités du cœur pour recueillir les pressions développées par la contraction de ces cavités, détermine, au premier moment, un léger trouble des mouvements cardiaques. Le plus souvent, ce trouble consiste en systole ventriculaires redoublées, qui se produisent irrégulièrement, de temps en temps, ou, plus rarement, avec une certaine régularité, dans une suite plus ou moins longue de révolutions cardiaques successives. Or ce trouble ne se traduit pas dans le tracé de l'oreillette, qui continue à battre avec un rythme à peu près normal. La figure 6 est un exemple intéressant du cas de dissociation fugitive. Deux contractions ventriculaires se rapprochent assez pour que la seconde puisse être considérée comme un redoublement de la première. Mais la contraction auriculaire correspondant à cette seconde systole du ventricule n'a pas, comme celle-ci, pris de l'avance; elle est restée à sa place normale et donne sa courbe, dans le tracé, juste au moment où va finir cette systole ventriculaire. C'est là une dissociation tout à fait typique.
English Translation
It is not rare that the presence of the ampoules introduced into the cardiac cavities, to record the pressure developed by the contraction of those cavities, immediately causes the onset of irregularity in cardiac movement. The cardiac difficulty consists of coupled ventricular systoles which produced irregularity from time to time, sometimes infrequently and sometimes with a certain regularity over a longer or shorter time during successive cardiac cycles. This difficulty did not translate to the auricle, which continued to beat with an almost normal rhythm.
Figure 6 is an interesting example of a single instance of dissociation. Two ventricular contractions approached each other so that the second could be considered to be a duplicate of the first. The auricular contraction did not correspond to the second ventricular contraction, but because of the advance of the ventricular contraction (ie prematurity ) it remained in its normal position and beat, in the tracing, just at the instant of the end of the ventricular systole. This is a typical instance of dissociation.
Chauveau MA. Rev. de Méd. Tome V. - Mars 1885: 161-173.
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"Animal Heat" and the Horse
Some of the earliest intracardiac studies were performed by Claude Bernard in 1844, and they involved measuring the temperature of blood in the right and left ventricles of a horse, which, in Bernard's words, was "alive and on its feet." Bernard and his mentor Francois Magendie were investigating a controversy on the "source of animal heat." By threading two long thermometers, one by way of the carotid artery and the other by way of the jugular vein, into the heart, they found that blood in the right ventricle was slightly warmer than that in the left ventricle, showing that heat generation occurred in the systemic, not the pulmonary, circulation. Bernard's approach was suitable for measuring relatively stable phenomena, but he lacked the ability to record more dynamic events. Figure 1: Apparatus used by Bernard in his temperature experiments. (Source: National Library of Medicine)
Carlson PA. Three contributors to cardiac catheterization. J Thorac Cardiovasc Surg 1980;79:782-788.
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Atrio-Ventricular Dissociation in the Horse 
Chauveau A. De La Dissociation Du Rythme Auriculaire et du Rythme Ventriculaire
Le cas que je vais signaler est très rare; c'est probablement le premier publié. Il mérite d'attirer tout particulièrement l'attention, car il est fort curieux et très intéressant au point de vue physiologique. Il s'agit d'un malade sur lequel l'oreillette battait avec son rythme normal, 60 à 65 fois par minute, tandis que le ventricule battait avec un rythme extrêmement ralenti, 21 à 24 fois par minute.
On sait, qu'à l'état physiologique, les deux rythmes sont étroitement associés, absolument dépendants l'un de l'autre; l'oreillette se contracte et le ventricule suit; chaque révolution du cœur comporte une systole auriculaire brève, nécessairement couplée avec une systole ventriculaire relativement longue. Ici les deaux organes, oreillette et ventricule, jouaient d'une manière tout à fait indépendante. Chacun semblait travailler pour son compte sans se soucier du travail du voisin, et cela, d'une manière constante, permanente; jamais les deux organes ne s'influençaient réciproquement, si ce n'est quand leurs mouvements coïncidaient dans une de ces rencontres fortuites que la discordance régulière des deux rythmes amenait forcément d'une manière périodique.
English Translation
The case that I will describe is very rare; this is probably the first publication. It merits paying particular attention because it is very curious and interesting from the physiologic perspective.
It describes a patient whose atrium beats with its normal rhythm, 60-65 times per minute, while the ventricle beats with an extremely slow rhythm, 21-24 times per minute.
We know that in the physiologic state, the two rhythms are strictly associated, absolutely dependent one on the other; the auricle contracts and the ventricle follows; each cardiac cycle consists of a brief auricular systole, necessarily coupled with a relatively long ventricular systole. Here, the two organs, auricle and ventricle, play in a completely independent manner. Each seems to work on its own in a constant fashion permanently; never do the two organs influence each other reciprocally. They never work together except when, by chance periodically, the two rhythms work together more forcefully.
Chauveau MA. Rev. de Méd. Tome V. - Mars 1885:161-173
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First Graphic Documentation of Ventricular Fibrillation
In 1849, while investigating vagal influences on cardiac activity, Hoffa, in Ludwig's laboratory, documented bizarre unregulated actions of the ventricles when exposed directly to strong faradic or constant currents. The disorder affected both rhythm and intensity, persisted after termination of electroexcitation and stopped cardiac output. The atria did not participate in the arrhythmia. Some of the hearts of dogs and cats resumed beating after standstill when cold calf blood was injected into the coronary arteries. The phenomenon unnamed by its discoverers, acquired numerous names subsequently, mouvements tremulatoires; tremblotements musculaires; tremulations musculaires; folie fibrillaire; mouvements fibrillaires; fremissements fibrillaires; delirium cordis; herz-delirium;herzflimmern; kammerflimmern; fibrillar contractions; intervermiform movements; ventricular fibrillation; undulatory movements; intervermicular actions; etc. Hoffa M,Ludwig C.,Ztschrft Rat Med 1850; 9:107
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Electrical Stimulation of the Heart in Man - 1889 In certain forms of cardiac arrest there appears to be a possibility of restoring by artificial means the rhythmic beat, and tiding over a sudden and temporary danger. Such is especially the case in those instances where cardiac failure assumes the form of an inhibition of the heart beat by impulses reaching the organ along the vagus nerves. There is much reason to believe that among cases of sudden and fatal syncope such a mode of heart failure is not very rare. As regards the means to be employed for the purpose of directly stimulating the cardiac action in cases of sudden failure, various expedients have been recommended - among others the application of galvanic and faradic currents to the region of the heart, electro-puncture, mechanical irritation by a fine needle passed into the organ, and the application of heat to the præcordia.
We want a much more effective and speedy mode of exciting rhythmic contraction, and one that will have a direct and powerful influence in calling forth a series of beats in the depressed or inhibited heart, while at the same time free from the danger of throwing the ventricles into delirium. Such a mode of excitation seems to be available in the form of a periodic series of single induction shocks sent through the heart at approximately the normal rate of cardiac action. A single induction shock readily causes a beat in an inhibited heart, and a regular series of induction shocks (for example, sixty or seventy per minute) gives a regular series of heartbeats at the same rate. Never on any occasion have I seen fibrillar contraction excited by such a mode of stimulation.
A series of single induction shocks excites a corresponding series of cardiac beats; the ventricular contraction precedes the auricular contraction when the exciting shocks are applied to the ventricles. Each systole causes the ejection of a considerable amount of blood into the aorta and pulmonary artery, and a marked rise of the blood-pressure at each beat. The mean pressure is raised from the low point to which it had fallen in consequence of the cardiac standstill; it does not, however, attain the normal height, even though a long series of beats is elicited by the stimulating shocks.
In order that such excitation should be as effective as possible it is probably best to send the stimulating shocks through the whole heart, so that the auricles may come directly under their influence as well as the ventricles. In order to do this in man one electrode should be applied in front over the area of cardiac impulse, and the other over the region of the fourth dorsal vertebra behind, so that the induction shocks may traverse the organ. The electrodes should be of considerable extent (for example, large sponge electrodes), and they and the skin should be well moistened with salt solution. The shocks employed should be strong, sufficient to excite powerful contraction in the voluntary muscles. Such a method, it seems to me, is the only rational and effective one for stimulating by direct means the action of a heart which has been suddenly enfeebled or arrested in diastole by causes of a temporary and transient character. Of course, at the same time, the expedient of artificial respiration must by no means be neglected, but, on the contrary, most sedulously attended to.
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McWilliam JA. Electrical stimulation of the heart in man. Brit Med J 1889;1:348-350.
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Voltaic Pile 
At the end of the eighteenth century and the beginning of the nineteenth, intense interest existed in electrical phenomena. Almost all were variations of the production and study of static electricity. In Italy during the 1780s, Luigi Galvani had been able to demonstrate that touching the amputated but still moist legs of a frog with two separate metal wires, eg copper and zinc, would cause them to contract, sometimes vigorously. During experiments with the legs of warm blooded animals in which the nerves to the legs were attached to iron wires and the feet to the ground during a thunderstorm, the muscles would contract convulsively during a lightning discharge. Following these and other similar experiments, Galvani became persuaded that all of these preparations demonstrated the existence of electrical capacity in biological forms and propounded a broad theory of animal electricity which he published in 1791. This theory was soon widely accepted but Galvani did not advance upon it when it eventually came under attack, largely by his countryman Alessandro Volta.
When Volta began to study electricity he was initially persuaded of the correctness of Galvani's theory, but gradually began to believe that it was incorrect following self experimentation with dissimilar metals placed on his own tongue and forehead during which his tongue quivered and he developed a sour taste which he interpreted as being caused by an electric flow. He eventually conceived that electricity was produced by the contact of two dissimilar metals, eg zinc and copper, and liquid which might be moist biological tissue. He proposed the term metallic electricity and that this electricity resulted from the contact of dissimilar metals with moisture (eg moist paper or cloth) and that biological tissue played no specific role.
Volta soon demonstrated that placing two metals (i.e. coins) in direct contact did not produce electricity, but would produce electrical flow if the two pieces of metal were separated by a moist conductor and were in contact or if another metallic conductor connected the two separated pieces of metal. He named such a combination a galvanic element and soon multiplied the effects of a single element by combining a large number into a pile which he initially described in 1800. He described the construction of a pile as: "Thirty, forty, sixty or more pieces of copper, or better of silver, each applied to a piece of tin, or, much better still, of zinc; and an equal number of layers of water or of some other liquid which may be a better conductor than simple water, such as brine, lye or pieces of card, skin, etc., well soaked in these liquids, such layers being interposed between each pair or combination of two different metals, one each alternate series, and always in the same order, of these three kinds of conductors, is all that constitutes my new instrument."
Volta A. in Wolf A. A History of Science Technology and Philosophy, Philosophical Transactions 1800
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