35 Mephitic Gases in Mines. gases; and the results of these experiments, | plied, are also dwelt upon The paper, above referred to, notes the praise-worthy efforts of Sir H. Davy; the result of which was the far-famed safetylamp; which, if it were universally and invariably in use, would go far towards preventing many of the direful effects of fire-damp; while it laments that, "notwithstanding this admirable precautionary vehicle is now generally known, and almost universally in use, it appears that no such effects have followed this general knowledge and use as the public fondly expected. The mephitic gases of mines yet suffocate miners, and ever and anon explode, producing effects the most terrific and disastrous. "Carburetted and subcarburetted hydrogen issue from the cavities of mines during the progress of the works, as these cavities are brought to the surfaces of these works, and, as that which acted as a dam to these receptacles of gas, is from time to time removed. So that the issues of gas into mines are incessant: yet these issues are, more or less, according to a variety of circumstances which occur in working; and which it would be endless, as well as useless, to enumerate. To provide, therefore, against this evil must be a daily task." 36 in that paper at The efficacy of lime as a disinfector may be deduced from two notable examples: the first is contained in, "A Walk to Vincennes," which states that, "During the reign of terror in France, one thousand two hundred and ninety-eight human bodies were interred, from June 24, 1793, to July 27, 1794, in a small garden in the Fauxbourg St. Antoine. Over each layer of bodies, layers of quicklime, several inches in thickness, were deposited. Although these remains must have constituted a mass of human putrefaction quite appalling, the lime effectually prevented any bad consequences to the living; and the decomposition was rapid and complete. The body of the notorious Baron Trenck was one of the one thousand two hundred and ninety-eight thus interred." The other example is French also: "M. M. Orfila, Leseure, Gerdy, and Hennelle, having to examine the body of an individual supposed to have been poisoned, and who had been dead nearly a month, found the smell so insupportable, that they were induced to try the application of the chloride of lime, as recommended by M. Labarraque. A solution of this substance was, therefore, frequently sprinkled over the body, and produced quite a wonderful effect; for, scarcely had they completely besprinkled the body, when the unpleasant odour was instantly destroyed, and the operation could be proceeded in with comparative comfort." In the first example we behold quicklime, without any accompaniment, performing the important office of a disinfector, by simple contact with the malignant substances; and this office it perform.ed so effectually, that the mephitic gases generated amidst these substances were completely neutralized as they were generated, and all contagion was prevented. From such an immense mass of putrefaction, what could have ensued, but the most direful pestilences to the living? these pestilences were arrested in embryo by this simple substance, and never, in a single instance, were able to rear their heads. So imposing is this effect, that it arrests our attention: we cannot move forward without seriously contemplating this powerful agent. But Among the remedies there prescribed are : A more copious introduction of atmospheric air into the works, than is in general introduced into mines. The exposure of quicklime in all parts of a mine; and slacking certain portions thereof, suddenly, with water, in such parts as are materially infested with gas. The evaporating of alcohol, by a slow heat, so as to cause the vapour of this liquid to insensibly fill those compartments of the mine which are in danger from the accumulation of gas. The introduction of lime-water, as well as lime in an impalpable powder. The evaporation of acetic acid, either alone or mingled with alcohol. The great caution needful in the use of unmixed alcohol, lest it should become inflamed; and the yet greater caution needed in the use of a lamp, in order to evaporate this, or any other liquid, lest it should produce an explosion of the But many will ask, what bearing has gases within the mine. The reasons why this example upon the operations of methese several substances are recommended, phitic gases in mines? The answer, howas likely to abate the evils arising from the ever, is at hand. Carburetted hydrogen, presence and action of mephitic gases, and subcarburetted hydrogen, or carbonic acid the several modes by which they may be ap-gas, are the mephitic gases which, in mines, subterraneous caverns, pits, and vaults, as well as in bogs and stagnant ditches, endanger animal life, by sudden combustion or insensible suffocation; in some cases producing a lingering, and in others instantaneous death; and these are the gases which are emitted from matter under the process of putrefaction. Whatever, therefore, is a disinfector in the one case, may become a disinfector in the other. We have seen that simple contact was alone necessary in the notable example furnished; and perhaps we have only to point out the means of bringing these gases and quicklime into contact, in order to their being as completely neutralized as the others were. (To be continued.) ON LATENT INSANITY. To man, the mind of man is of infinite importance; and to say nothing of its improvements, every one possessing intellectual powers, should be acquainted with the causes that so often produce the most deplorable effects upon those powers. It is not sufficient that a few professional men should study mental diseases; for such is their nature, that they may have made fatal progress before any, but those affected, are at all apprised of their approach: and the best chance of success, both as to prevention and cure, can only be expected, when those visited by the previous symptoms do themselves know something of their nature, and the means of prevention. This I have repeatedly urged; but so long as palpably visible insanity is preposterously treated, as it certainly is in many instances, it is not likely that obscure symptoms shall meet with judicious treatment, either medical or moral. While thousands of deeds of horror are committed by those who are acknowledged to have been insane at the time, tens of thousands are perpetrated under its influence the disease being latent, or doubt.. ful, in the minds of others. The great cause of obscurity in what may be called latent insanity, arises from the disease being thought disgraceful. If those afflicted, or in danger of an attack, were as ready to speak of their symptoms, as of the symptoms of approaching gout, insanity might be generally prevented under skilful practice. But it is as vain to expect the patient to reason correctly under a paroxysm of mental disorder, as to prevail upon those to speak truly of their symptoms who have any idea that approaching insanity is suspected. It would be a great point gained, if those in actual danger could be brought to a secret conviction that they are liable to it. The proofs of latent insanity, with which thousands are afflicted, can only be known to themselves, and the marks of visible insanity are confined to the looks, the words, and the actions; and these are often equivocal, for the disease being partial and intermittent, there may be a total absence of any appearance of it, both in the words and actions, during what are called the lucid intervals; and though the looks are a more steady and certain criterion, yet they cannot be acted upon as evidence. I have seen numbers in my time, whose looks were a strong indication of mental disorder, to whom the disease had never been imputed. And, indeed, I have known others whose conduct and language were plain proofs of insanity, (and of their being afflicted, I have had secret evidence on which I could depend,) to whom it had not been imputed, except by those who had made the complaint a study. We have now an instance of this in a man of blasphemous notoriety. That the subject is of vast importance, is proved by the great numbers who are visited by insanity, and the deplorable proportion of those who do not recover from it, and the numberless acts that are committed under its latent influences, in the face of evidence that the disease might almost always be prevented, (and when not prevented, it might almost always be perfectly cured,) if proper measures were timely resorted to, and duly persisted in. That all who have the common imaginations, and sensibilities, and mental energies, of human nature, are liable to insanity, none will dispute who understand the disease; for, in fact, it is only the excess of what we all experience, with the exception of those who are under the influence of extreme apathy or afflictive idiotism. If, then, all are liable to this dreadful malady to whom life is valuable, it is a great blessing, that a knowledge of its approach, and of the means of prevention, is attainable; yet how few seem to wish for this knowledge. People will talk of the horrors of insanity; but did they truly know them, as those in my situation must know them, surely they would not fail to cultivate a knowledge of the means of preventing its attacks, for themselves, and those near and dear to them in life. To me it appears an highly imperative duty in all, to acquire all the information possible upon the subject, and to get rid of those prejudices and that ignorance, which render the study of it so repulsive to the feelings. How can those who do not 39 Essays on Physiology: Essay III. possess any information upon the subject, have any well-grounded confidence that they shall not themselves be afflicted with this disease; that they shall not have their most ardent feelings and affections perverted so as to hate those they now most love; that they shall not be brought by it to blaspheme their Maker and God, or murder themselves, or those now most near and dear to them? When the person before alluded to expressed the warmest feelings of true devotion, which I am assured he once did, could he suppose that he should, at a future day, be brought to trial for blasphemy, under the influence of a disease so disguised as to consign him to the ignominy and sufferings of a common prison, instead of an asylum for the insane? Insanity, as I have said before, is not any deprivation of knowledge, or of the reasoning powers; on the contrary, knowledge, and the powers of reason, may receive improvement under the excitement of it. It is a disease which, at times, and upon some subjects, prevents the exercise of the reasoning powers, or excites them to a disordered excess; but take away the disease, and the reasoning powers are left uninjured, if not improved; which could not be the case, if the faculties of the mind had been diseased. The most perfect state of sanity is that in which the involuntary thoughts and feelings are the least acted upon by adventitious and improper impressions, and are at all times in the best state of temperance. Still, as we are all troubled with wanderings, absence of thought, and visionary ideas, and also are subject to over strong feelings and passions, we have all the germ or seed of mental disease, and it is only in degree we differ, the excess becomes insanity. In some, confusion of the ideas, and the violence of the passions, are a thing of habit, and do not produce actual insanity, or permanent madness. I know a man whose violence of temper, vindictiveness, and horrid oaths, upon the most trifling occasions, would stamp him a madman, were it not that he has been so all his life: and it is in the changes which take place in the temper and habits, that we are to find matter for apprehending the approach of insanity in others. Those who attend to their own involuntary thoughts, and feelings, and habits, as all should do, may be well aware of its approach, long before it is visible to others. Admitting that the remote cause of insanity may be mental, I must still contend that the immediate or proximate cause is always physical. For extreme grief or joy, 40 or anxious suspense, will cause those physi. cal affections that may, with confidence, be stated as the immediate cause of the mental aberrations called insanity. For my best directions respecting the prevention and cure of mental derangement, or insanity, I beg to refer my readers to my former letters published in the Imperial Magazine. THOMAS BAKEWELL. Spring Vale, near Stone. ESSAYS ON PHYSIOLOGY, OR THE LAWS OF ORGANIC LIFE. (Continued from Vol. IX. col. 1111.) ESSAY III. On the Powers by which the Operations of the Organic Frame are carried on. We have stated, that every organized body is endowed with that principle, to which we have given the term sensibility; and we would now, in continuance of the subject, observe, that the sensibility of each part, or organ, is peculiar to itself; that is, although sensibility is universally diffused throughout every part of the frame, yet each possessing only its own peculiarly modified sensibility, lives, feels, and moves, after its own way. Thus, for instance, stimuli which affect one organ, produce no impression on others; as the eye is insensible to sound, the ear to light. Still, although the sensibility of all the organs is thus modified, and peculiar to themselves, the whole conjunctively work together to one common end, their mutual preservation and improvement, and the preservation of the individual. With regard to contractility, which may be said uniformly to accompany sensibility, there is one modification which I have hitherto omitted to mention,―a modification, which organs in a healthy state never exhibit, when influenced by their natural and proper stimuli, namely, contractility at the same time involuntary and sentient, or perceived, that is to say, an action which occurs independent of the will, over which the will has no power, and of which we have at the same time complete perception; as in the example of an electric shock, which, as every one knows, will produce powerful muscular contractions, perfectly involuntary, of which, however, we are as perfectly aware. Voluntary and perceived contractility attends upon, or is associated with, percipient sensibility; or, as it may be termed, perceptibility. Involuntary and insensible contractility is associated with latent sensibility. From this view, we may easily satisfy In childhood and youth, these two proourselves of the existence of two modes of perties are in the greatest activity and perfeeling, and of two sorts of motion,-a | fection; but as age advances, they diminish sensibility, by virtue of which certain parts more and more rapidly till death. The send to the brain the impressions they livelinesss and frequency of impressions receive, to be there objects of conscious- quickly wear out, and exhaust the sensibiness, and by which we are aware of our lity; and in organs, as, for instance, the own existence, as well as of that of the natural muscles that have been long exercised, conworld around us; and a different mode of tractility shares the same fate, and rest and sensibility, belonging to all organs without repose are necessary, as it were, for their exception, and which are all that some refreshment, when the properties are again possess. These are adapted and sufficient restored to their natural energy. for the exercise of the functions of nutrition, and by means of which the organs appropriated to this purpose are kept in action, and preserved in their natural state. There are also two kinds of contractility,the one in virtue of which certain organs, obedient to the will, exercise the contractions which it determines; the other, independent of the will, and which manifests itself by actions, of which we have no more intimation than we have of the impressions by which they are determined, This latter modification of sensibility and contractility, is that which we see manifested by vegetable life, and which many species, as the sensitive plant, the fly-trap, and others, so remarkably exhibit. The latent sensibility, however associated to animal life, at least in the higher orders, differs considerably in one of its characters from that of the vegetable world, viz. the power it has of being altered and modified by circumstances, and of elevating itself to perception; and we would observe, that when organs endowed with this species of sensibility become the subjects of disease, they assume a new character, and manifest a percipient sensibility-often acute to the highest degree. The stomach, for example, when in health, possesses no conscious perception of the presence of natural food, which, when that organ is suffering under inflammation, produces the most intense pain. On the contrary, we find that percipient sensibility may be altered by habit, (with reason termed second nature,) and degenerate into the latent: so that what before was felt, and even occasioned pain or uneasiness, ceases at length to communicate sensation. Sensibility and contractility, which offer very considerable shades of modification and difference in different individuals, according to age, sex, temperament, &c., have been by physiologists not unaptly compared to a fluid flowing from a given source, which may be exhausted and replenished, drained and consumed, distributed equally or unequally, or occasionally even concentrated in peculiar parts. 109.-VOL. X. Under particular circumstances, sensibility appears to forsake every part of the system, and to become as it were concentrated in one part or organ; the rest appearing at the same time almost totally deprived of it. For instance, if any part be suffering acute pain, or agony,-and uneasiness or pain of a more moderate degree be inflicted in another part,-this, (which otherwise would have been felt as irksome,) during the continuance of the more violent, will not be regarded, or even noticed. During sleep, percipient sensibility and voluntary contraction are in some measure suspended; and this suspension is either more or less complete, according to the healthy soundness of the repose. In the warm climates of the south, it is observed, that sensibility is more lively, and more easily excited, than in the inhabitants of more cold and northern regions. In the natives of Italy and Spain, and especially of Africa, we find a sensibility irritable to the highest degree: in the latter, it often happens that the slightest wounds produce convulsions, locked jaw, and death; which are of comparatively unfrequent occur. rence in these northern climates, as sequels to trifling injuries, and then only in persons of a morbidly irritable constitution. When the muscular powers are more than usually developed, the nervous powers, if I may use the expression, appear to suffer a proportionate diminution; that is, there appears to exist a kind of opposition between the force of muscular contraction and the sensibility of the nerves. Hence it is observed, that those whose athletic force is immense, are sluggish in their motions, contracted in their intellects, and with difficulty roused to active exertion of any kind: they are, for the most part, but slightly affected by ordinary impressions. It seems as if an extra degree of stimulus were required to rouse the slumbering energy of the muscular powers, which, when once roused, and not till then, display the extent of their efficacy. The sensibility which the higher orders of animals possess, depends, as we have before D 43 Essays on Physiology: Essay III. SO stated, upon the nerves, and is in fact a property connected with them, and essentially inseparable from their nature; but those animals which possess no distinct nervous system, or rather perhaps in whose contexture distinct nerves have not been discovered, appear at once endowed with sensibility (latent,) and its companion, contractility, in all their parts and organs; throughout the structure of which it would seem that they were essentially diffused; and indeed in these orders of beings, the two properties just mentioned are blended, that the separate existence of each as a distinct principle, cannot be conceived or understood, except as abstract qualities. Percipient sensibility or perceptibility, is the power which certain nerves possess of receiving an impression, and of transmitting it to the brain, and the impression thus received is termed a sensation. have stated before; but it may be asked, Is it proved that the nerves are the organs of sensation? or that they do transmit impressions to the brain? For the proof of this, we can appeal to observations and numberless experiments;-it is found, for example, that if any principal nerve be divided, or even compressed, the part or organ over which such nerve is distributed, becomes at once insensible. Thus, if the optic nerve be injured, loss of vision is the consequence; if the spinal cord be hurt, the limbs below the injury become paralyzed ;if the brain be suffering pressure, either from too great a volume of blood circulating in the vessels ramifying over it, or from blood effused upon its surface, apoplexy, paralysis, and death, are the results. This we In advancing to direct our inquiries respecting the impressions received through that power of the nerves termed percipient sensibility, we shall observe, in limine, that a distinction is to be drawn between the vividness of sensation, and the accuracy with which the mind judges of objects by sensation, or, as it is termed, accuracy of feeling. The first time that any stimulus acts upon the senses, it in general produces a vivid sensation; but the liveliness and vividness of impressions become diminished in proportion as the action of such stimulus on the senses is repeated; and by these means, the sensation may be at length almost annihilated; which effect is produced in common language by habit. Sensations can, in some degree, be rendered, at will, more vivid and intense; and the author of our frame has also endowed us with the faculty of moderating and diminishing them. Thus, if we wish to 44 render a sensation as impressive as possible, we dispose the organs of sensation in the most advantageous manner, we direct the whole nervous sensibility to one particular part, we receive but a small number of impressions at the same time, applying all our attention to them :-hence, a great difference is established between merely seeing, and regarding attentively; between hearing, and listening. On the other hand, when we wish to moderate the vivacity of any sensation, we either generalize (if the term be allowed) the nervous sensibility, or direct it intently to another object;-for instance, if I happen to be in a room where conversation is passing, to which I wish not to listen; if I direct, by a sort of mental force, my attention to some object, as the examination of a painting, or engage myself in thinking on a subject which requires a more than common exertion of the mind,-I shall not hear a word of what is spoken; and the same effect will be produced, if I abstract my attention totally from every thing around me, and fix my thoughts, as it were, on vacancy, assuming a state of mental abstraction, called reverie. We have already previously observed, that it is through the medium of sensation we become aware of our own existence, and the existence of surrounding objects. The sensations by which we acquire this knowledge, various and complex as they may be, have been, by some writers, referred ultimately to two classes, viz. pleasure and pain; and although numberless sensations which we perpetually experience, appear to excite in us neither the one nor the other, we must not too hastily conclude that this arrangement is without foundation; for let us reflect on the modification which habit produces-how soon even pain beż comes less irksome, and pleasure a matter of indifference; and remember how those circumstances, which on their first occur rence produced feelings of delight, are now little noticed by their continuance or frequency; at the same time considering also, how in childhood, when the system is as yet new to the crowd of sensations which are about to call forth the exercise of untried faculties, no occurrence is indifferent, but a cause, either of pleasure or of pain, and we shall be more ready to yield our assent. Besides, too, it must be allowed, that although numberless sensations (and it is wisely so ordered by Providence) do not draw us from our duties by the pleasure or pain they communicate, a slight or unusual increase of any of such sensations immediately determines it decisively to the one state of feeling or the other. |