Part 69

It may be said that these opinions were similar to those of the Ovarians, who, as we have observed already, believed that every thing arose from the egg. Such were Aristotle, Empedocles, and other philosophers: "For the egg is the conception," said the first of these great men, "and after the same manner the animal is created;" but there was a manifest difference in their systems. Harvey, Haller, De Graef, were amongst the most warm advocates of this doctrine, which indeed prevails to the present day, as it would be difficult to find organized beings that did not spring from an original germ.

It thus appears that, notwithstanding the absurd doctrines of generation being founded upon the existence of these animalcules, they clearly do exist. Modern microscopic experiments daily confirm the fact; not only in the generative secretion, but in the other fluids of the body: creatures of an inch to an inch and a quarter in length have been found to inhabit the mesenteric arteries of asses and horses. Mr. Hodgson found them in seven asses out of nine. They have also been found in the blood of female frogs, salamanders, and tadpoles. What wonders are perhaps in store for the microscopic observer and the physiologist! All living matter seems to be animated by particles, by atoms, equally possessed of life. Does the vitality of these constituent molecules hold any influence over our existence? Is their life necessary to the preservation of ours? Is any agency destructive to them injurious or destructive to us? In a former paper I have recorded recent observations, where animalcules of a peculiar description were found in the purulent secretion attending various affections. A morbid condition seems thus to produce a new series of animated beings, or this new series of living atoms perhaps have produced a morbid state. Many eruptive maladies are either caused by the presence of insects, or insects are subsequently developed in their pustules. Wichmann, and many other physicians, have maintained that the itch was produced by an insect of the genus acarus, or tick.

Latreille has given a minute description of this creature in his Genera crustaceorum et insectorum, and calls this offensive species the sarcoptes scabiei. Linnaeus classed it among the aptera, and termed it the acarus scabiei. This insect is nearly round, with eight legs; the four fore-legs terminated with a small head, the hind ones with a silky filament. The Arabian Avenzoar had long since observed them, and it was from his writings that Mouffet was induced to pursue the inquiry. Redi, an Italian physician, was the first propagator of this doctrine in modern times, and published, in 1685, a paper of Cestoni of Leghorn, who had frequently observed mendicants and galley-slaves extracting these insects from the pustules of itch with the point of a pin, in the same manner as chigoes are extracted from their cyst in the West Indies.

It was this communication of Cestoni that led to a further and more minute investigation. Curiosity was every where excited, and the most learned and intelligent naturalists and physicians, amongst whom we find the illustrious names of Borelli, Etmuller, Mead, Pringle, Pallas, Bonani, Linnaeus, Morgagni, strove with incessant diligence to ascertain this important fact, which certainly was likely to shed a new light on our pathological speculations. The existence of the acarus was established.

The most conclusive experiments on the subject were those of Gales, in 1812. The following is the account of them: "I placed under a microscope a watch-glass with a drop of distilled water, after having carefully ascertained that it did not contain any visible animalcules. I then extracted from an itch pustule a small portion of the virus, which I diluted in the water with the point of a lancet. I watched most attentively for upwards of ten minutes, without having been able to notice any animation. Two similar experiments were equally ineffectual. Disappointed in my expectations, I was about giving up the task, when an idea struck me of submitting the liquid of the first experiment to another trial. I had left it in the watch-glass, exposed to solar heat. I then was not a little surprised when I discovered a perfect insect struggling with its legs to extricate itself from the viscid fluid that confined it. Having succeeded in reaching a more limpid part of the liquor, its form was so distinct that Mr. Patrix, who was with me, was enabled to take an exact drawing of its configuration."

This curious result naturally induced Gales to pursue his inquiries, and he discovered that this insect chiefly occupies the pustules that are filled with a thin serum, and avoids those that contain a thicker secretion. Hence the watery pimples in itch are invariably those that produce the most intolerable prurience.

The next important question was to decide whether this insect was the cause of the disgusting disorder. For this purpose Gales placed several of them on the back of his hand. He then covered the part with a small watch-glass, kept in place with a bandage. Three hours after he awoke, experiencing a sensation of itching on the part. The following morning three itch pustules were evident, and convinced him that he had succeeded in inoculating himself with the loathsome complaint. This fact he communicated to Olivier, Dumeril, Latreille, and Richerand. Experiments in the hospital were immediately directed to be made, and all produced a similar result; affording a convincing proof that these insects could produce the affection, which they had merely been thought to have complicated.

Many writers, who, like Mason Good, had decided that "whenever these insects appear, they are not a cause but a consequence of the disease," opposed and contradicted the statement of Gales, and the numerous practitioners who had procured and witnessed facts, which are never "stubborn things" to speculative minds. These writers maintained that whenever any organ was weakened, or in a morbid condition, it was apt to become a nidus for some insects or worms to burrow in. Hence the numerous varieties of invermination in debility of the digestive organs. But it is needless to observe that their objections cannot stand against the imbodied evidence brought forward in proof of their error. Bosc, Huzard, Latreille, Dumeril, and many other naturalists, subsequently found these acari in the eruptive diseases of many animals.

I repeat it, this subject is replete with interest; and microscopic experiments may some time or other throw a material light on the practice of medicine. Those substances that are known to destroy the insect that produces the itch, cure the malady. May not this analogy lead to singular results?

CIRCULATION OF THE BLOOD.

The circulation of the blood was first taught by the unfortunate Servetus in 1553, who was burnt to death as a heretic; and, a century afterwards, demonstrated by our Harvey, who is justly considered as having discovered the wonderful mechanism of the motion of the vital fluid.

There is no doubt, however, that the ancients had formed, if not a correct, at least an ingenious, idea of it. Hippocrates tells us "that all the veins communicate with each other, and flow from one vessel into others; and that all the veins that are spread over the body carry a flux and movement originating in a single vessel." He avows that he is ignorant of the principle whence it arises, or of its termination, it appearing to be a circle without beginning or end. He further states, that the heart is the source of the arteries, through which blood is carried over the body, communicating life and heat; and he adds, that they are so many rivulets that irrigate the system, and carry vitality into every part: the heart and veins are in constant motion; and he compares the circulation of blood to the course of rivers, that return to their source by extraordinary deviations. He therefore directs blood-letting to restore a free current of the blood and other spirits in apoplexies and other diseases of a similar nature, which he attributed to obstruction in the vessels intercepting the flow of their contents. He also observes, that when bile enters the blood, it deranges its consistence, and disturbs its ordinary course towards another point: and he compares the circulation to balls of thread, the threads of which return to each other in a circuitous manner, terminating at the point whence their motion arose.

Plato thought that the heart was the source of the veins, and of the blood, that was rapidly borne to every part of the body. Aristotle tells us that the heart is the principle and source of the veins and of the blood. He considered that there were two veins proceeding from this organ, one from the left side, the other from the right; the first he termed aorta: and he further maintained that the arteries communicated with the veins, with which they were intimately connected.

Julius Pollux taught, in his Gnomasticon, that the arteries are the channels through which the spirits circulate as the veins propel the blood; and he describes the heart as having two cavities, one communicating with the arteries, and the other with the veins. Apuleius tells his disciples that the heart propels the blood through the lungs, to be afterwards distributed over the system.

In the writings of Nemesius, bishop of Emissa, we read that the movement observed in the pulse originates in the heart, chiefly from the artery of the left ventricle of the viscus. This artery is dilated, and then contracted, by a constant and powerful harmonious action. When dilated the vessel draws towards it the most subtile portions of the neighbouring blood, and the vapour or exhalation of this fluid, that feeds the animal spirits; but when it contracts, it exhales, through various channels of the body, all the vapours that it contains.

Strange as it may appear, doubts were once entertained as to the actual situation of the heart, whether it was lodged in the right or the left side of the body. The question was finally settled by a professor of Heidelberg, who for the purpose killed a pig in the presence of the Margrave of Baden, Durlach, who then laboured under a supposed disease of that organ, which it was then clearly shown occupied the left side. The result of this experiment, however proved somewhat detrimental to his Highness's physician, who was dismissed, although he maintained with all becoming courtesy and respect, that the heart of his princely master could not possibly be in the same position as that of a hog.

Michael Servetus, in his work, De Christianismi restitutione, also in the 7th book, De Trinitate Divina, for which he was sentenced to the stake a very short time after its publication, gives us the following description of this important function: The blood, which is a vital spirit, is diffused all over the body by anastomoses, or inosculation of two vessels through their extremities. The air in the lungs contributes to the elaboration of the blood, which it draws for that purpose from the right ventricle of the heart through the pulmonary artery. This blood is prepared in the lungs by a movement of the air that agitates it, subtilizes it, and, finally, mingles it with that vital spirit which is afterwards retransmitted to the heart by the movement of the diastole, as a vital fluid proper to maintain life. This communication and preparation of the blood, he further states, is rendered evident by the union of the arteries and veins in this organ; and he concludes by affirming that the heart, having thus received the blood prepared by the lungs, transmits it through the artery of the left ventricle, or the aorta, to every part of the body.

Great care was of course taken to destroy this abominable heretical publication, which was burnt by the common hangman in Geneva, Frankfort, and several provinces of France. The work thence became so scarce, that it is said only three or four copies of it are in existence. One of them was in the library of the Landgrave of Hesse-Cassel.

John Leonicenus relates that the celebrated Paul Sarpi otherwise named Fra Paolo, had also discovered this circulation, and demonstrated the valves of the veins, which open to afford a free passage to the blood, and close to prevent its return. This discovery, it is pretended, was made known to Fabricius ab Aquapendente, professor of medicine in Padua in the sixteenth century, and successor of Fallopius, and who communicated the fact to Harvey, then a student in that university.

Some time before Harvey's discovery, Cesalpinus had described with great precision the pulmonary circulation; and, on finding that veins swelled under a ligature, he attributed this enlargement to the warmth of the blood. This warmth, he says, proceeds from a spirit residing in the blood. The left ventricle is filled with blood of a spirituous nature; and one can trace the movement of the blood towards the superior parts, and its return (retrocessus) to the internal ones,--that is to say, a return by which it comes back from the extremities to the heart, when awake or sleeping, from every part of the body; for if you tie the vessels, or if they are obstructed, the current of the blood is stopped, and then their smaller ramifications tumefy towards their origin. The following are his words: "Sic non obscurus est ejusmodi motus in quacumque corporis parte, si vinculum adhibeatur, aut alia ratione occludantur venae: cum enim tollitur permeatio, intumescunt rivuli qua parte fluere solent." From these expressions it is clear that Cesalpinus suspected the great circulation, and had a fair idea of its nature; yet there is no doubt but that it was to our Harvey that the first demonstration of this wondrous function was reserved.

DRUNKENNESS.

At all periods this degrading vice appears to have been more or less prevalent. We find it frequently mentioned in the early history of the Jews. Tacitus informs us that it was common amongst the ancient Germans; and in Greece and Rome it was not only common, but frequently extolled as beneficial--as medicinal:

Si nocturna tibi noceat potatio vini, Hora matutina rebibas, et erit medicina.

Socrates considered the indulgence in wine pardonable. Thus, C. Gallus:

Hoc quoque virtutem quondam certamine, magnum Socratem palmam promeruisse ferunt.

According to Horace, Cato the Censor had often recourse to its exhilarating virtues:

Narratur et prisci Catonis Saepe mero incaluisse virtus.

Seneca informs us that even the Roman ladies frequently indulged in these potations. The drunkenness of the ancients bore all the disgusting character of the present day, and was thus admirably described by Lucretius: