Popular Science Monthly/Volume 15/August 1879/Chloral and Other Narcotics I
| CHLORAL AND OTHER NARCOTICS. |
By Dr. BENJAMIN W. RICHARDSON, F. R .S.
I.
IT fell to my lot to be the first in this country to investigate the action of hydrate of chloral after the remarkable discovery of its properties as a narcotic by the distinguished and original Liebreich. At the meeting of the British Association, held at Exeter in the year 1868, the late Mr. Daniel Hanbury, F. R. S., brought with him to the meeting, from Germany, a specimen of the hydrate and a brief verbal account of the phenomena which it had been found to produce on living bodies. The facts related by Mr. Hanbury proved of so much interest to the members of the Biological Section, that they elected me, who had just been submitting a report on an allied subject, to make a further and special report during the meeting on this particular subject. I accepted the duty at once, and conducted a series of experimental researches, the results of which were duly laid before the section on the last day of the meeting. The results were among the most singular I had ever witnessed, and the report upon them raised an intense curiosity among the medical men and the men of science in this country. Liebreich's discovery became the physiological event of the year, and for some months I was engaged, at every leisure moment, in demonstrating the various and unique facts which that discovery had brought forth.
In this chloral hydrate we were found to possess an agent very soluble and manageable, which, introduced into the body of a man or other animal, quickly caused the deepest possible sleep, a sleep prolonged for many hours, and which could be brought so near to the sleep of death that an animal in it might pass for dead and still recover. In this substance we also found we had an agent which was actually decomposed within the blood, and which in its decomposition yielded the product chloroform which caused the sleep; a product which distilled over, as it were, from the blood into the nervous structure, and gave rise to the deep narcotism.
The discovery of Liebreich opened a new world of research, the lessons derived from which I shall never forget. And yet, now that ten years have passed away, and I have lived to see the influence on mankind of what is in one sense a beneficent, and in another sense a maleficent substance, I almost feel a regret that I took any part whatever in the introduction of the agent into the practice of healing and the art of medicine.
About three months after my report was read at the meeting of the British Association for the Advancement of Science the first painful experience resulting from chloral hydrate came under my knowledge. A medical man of middle age and comfortable circumstances took, either by accident or intention, what was computed to be a dose of 190 grains of chloral hydrate. He had bought, a few days before this event, 240 grains of the substance. He took a first dose of ten grains in order to procure sleep. On a following night he took twenty grains, and on the evening of the succeeding day twenty grains more. These administrations were known. He had reduced his store by these takings to 190 grains, and, while in a state of semi-consciousness from the last quantity, he got up from the bed on which he was reclining, and emptied all the remaining contents of the bottle into a small tumbler of water, and swallowed the large dose so prepared. He was found insensible, with the bottle and glass by his bedside. He did not fully regain consciousness for sixty hours, but finally made a good recovery.
The occurrence of this experience led me into a new line of research, namely, to find out what was the best mode of maintaining life while the body is under the influence of a deep sleep from the hydrate. This new research disclosed that the great object of treatment should be to sustain the animal temperature. I found that, like alcohol, the tendency of chloral hydrate is to reduce the vital fire, and that of two animals under chloral, one in a warm, the other in a cold atmosphere, the recovery of the one in the warm and the death of the one in the cold atmosphere could be reduced to a matter of positive system or rule. I had soon to publish that lesson, and to indicate that there were dangers ahead in respect to the use of chloral hydrate, which dangers would have to be scientifically combated.
Within a year after the introduction of chloral hydrate into medical use another new truth dawned on me. One morning the friends of a gentleman called on me, bringing a bottle of chloral hydrate and a copy of a medical paper containing a lecture of mine relating to the action of the drug. They had noticed for some time past that the gentleman, about whom they were anxious, had been very peculiar in manner, exhibiting signs resembling those of intoxication from alcohol, but with more than alcoholic somnolency. He was an alcoholic, and sometimes he was apt to have spells of inebriation; but the phenomena more recently observed were somewhat different. Watching him closely as their alarms increased, they detected that he was in the habit of dosing himself with some substance which he kept in a series of bottles, of which he had seventeen or eighteen in stock, and one of which they brought to me. The bottle they brought contained chloral hydrate, and it turned out that all the bottles contained, or had contained, the same. By and by this gentleman came to me himself, and confessed that he was in the habit of taking the chloral three or four times in the twenty-four hours. He took it at first, after reading my lecture on its medicinal uses, in order to procure sleep. It answered his purpose so well that he became induced to repeat the process, and in a little time got what he called his new craving. He presented a series of special symptoms from the chloral which had some of the characters of jaundice and some of the characters of scurvy. These symptoms were additional to the signs of brain and nervous disturbance caused by the chloroform derived from the chloral, and they were easily accounted for. The chloral, in undergoing decomposition within the body, divides into two products, the one chloroform, the other an alkaline formate, a soluble salt, which makes the blood unduly fluid, and acts much in the same manner—as I found again by direct experiment with it—that common salt does, or the mixture of pickling salts used for the preservation of dead animal tissues that are preserved by the process of salting.
Here, then, was another history of danger from the use of chloral hydrate, a new condition of disease to which I drew attention very speedily, and to which I gave the name of chloralism. It is a matter of deep regret to have to report that since the name was given to the disease chloralism has become rather wide-spread. It has not yet spread far among the female part of the community. It has not yet reached the poorer classes of either sex. Among the men of the middle class; among the most active of these in all its divisions—commercial, literary, legal, medical, philosophical, artistic, clerical—chloralism varying in intensity of evil has appeared. In every one of the classes I have named, and in some others, I have seen the sufferers from it, and have heard their testimony in relation to its effects on their organizations—effects exceedingly uniform, and, as a rule, exceedingly baneful.
The history of chloralism is of interest to the scholar of history as showing how easily a simple scientific discovery may be misapplied when its misapplication ministers to some luxurious desire or morbid inclination of mankind. I give the account at first hand, drawing upon no other experience than my own, an experience which dates from the first commencement of the disease, and which, during all the period, has been probably, in this country, as comprehensive as any in respect both to instances of acute and of slow mischief from this one cause. I could fill easily all the space allotted to me in the present essay by mere narration of observed facts on this topic, were that my object. My object does not lie in that direction, useful and practical though it might be. Let the reader simply remember that from a certain scientific basis of research something specifically social, and either moral or immoral in its tendencies, has occurred in a brief space of time, and that a singular mental phenomenon has been developed among the most cultivated representatives of a highly cultivated people, and the impression I wish now to indicate by the brief narrative recorded above is supplied.
This is not the first time in the history of mankind that the same kind of history has been written. There is a previous history, from which dates a great deal that is curious in romance and poetry, and which even to Shakespeare afforded a world of wonder and of story.
The ancient physicians, dating from Dioscorides himself, tell of the use of a wine made into a narcotic by mandragora. From the leaves and from the root of the Atropa mandragora the ancient physicians prepared a vinous solution which in many respects had the same properties as the chloral hydrate of to-day. This wine, called "morion," was given to those who were about to be subjected to painful surgical operations or to the cautery, so that, ere the sensitive structure was touched, the sick man was in a deep sleep during which the operation was performed without the consciousness of feeling, not to say of pain. The sleep would last for some hours. From this purely medical or surgical use of morion, the application of it extended. Those who were condemned to die by cruel and prolonged torture were permitted to taste its beneficence and to pass from their consummate agony through Lethe's walk to death. A little later and the wine of mandragora was sought after for other and less commendable purposes. There were those who drank of it for taste or pleasure; and who were spoken of as "mandragorites," as we might speak of alcoholics or chloralists. They passed into the land of sleep and dream, and waking up in scare and alarm were the screaming mandrakes of an ancient civilization.
I have myself made the "morion" of that civilization, have dispensed the prescription of Dioscorides and Pliny. The same chemist, Mr. Hanbury, who first put chloral into my hands for experiment, also procured for me the root of the true mandragora. From that root I made the morion, tested it on myself, tried its effects, and re-proved, after a lapse of perhaps four or five centuries, that it had all the properties originally ascribed to it. That it should have come into use as a narcotic by those who first tasted it for its narcotic action, and that they should have passed into mandragorites, is not more surprising than that other and later members of the human family should have become chloralists. The effects produced by morion subjectively and objectively are so much like those from chloral that they may be counted practically as the same. I have put these two examples of the action of two similar toxic agents in parallel positions, because they are remarkable as showing how, at most distant and distinct eras of civilization, a general practice in the use of these agents sprang out of a special practice relating to their use, a maleficent out of a beneficent purpose. If I wished to extend the comparison, I might place opium, ether, chloroform, and chlorodyne under the same category.
Mandragora, opium, chloral, ether, chloroform, chlorodyne, are medical agents used in the first instance mechanically, and used in a second instance socially, and by habit in certain instances, for the purpose of making the mind oblivious, or, in other and more frequently used words, for securing repose or rest. These agents do not stand alone in respect to the list of toxicants which are assumed to be useful to mankind. To them must be added many others which have not necessarily had an origin from medical science or art, but have sprung into general use from their first application. Under this head may be included the commoner members of the chemical families known as the alcohols: hasheesh from the Canabis indica (Indian hemp), yerba de nuaca, or red-thorn apple, almanitine, coca, absinthe, arsenic, tobacco.
It will be seen that the toxical agents are a numerous class, and, if I had chosen to refine, I might have added some further. In one notable instance, and in one or two less notable, nitrous-oxide gas, the gas now so commonly used by dentists as an anæsthetic, has been resorted to as an habitual stimulant and narcotic; but the rarity of its use prevents the necessity of doing more than referring to it in this place, and once perhaps again in the sequel. Of the other agents it may be said, in limine, respecting the extent of their use, that the alcohols and tobacco stand first on the list in our civilized life. Next after these come opium, absinthe, chloral hydrate, chlorodyne, ether, and chloroform. The other substances are local in the range of their employment. Hasheesh is an Eastern luxury; amanitine a Kamtchatkan luxury; arsenic a Styrian luxury; red-thorn apple a luxury of the Indians of the Andes, under the sweet influence of which they enter into communion, as they believe, with the spirits of their departed dead—the best excuse I have ever heard given for the use of any of these indulgences whatsoever.
As we cast our minds back upon this long list of toxical instruments for the delight of man, we are struck with the widely apparent difference that seems to exist between them. The difference, however, is not so great as it may seem, for between the physiological action of one and the other there is an analogy of action in certain particulars which is singularly striking. As a rule, the key-note of the action of these agents, if I may use such a simile, is through one particular element where many elements enter into their composition. Where nitrogen is present as an element, a definite line of action of the agent is marked out; when a hydrocarbon radical is dominant—that is to say, when such a radical forms the chief part of the compound—the influence of that is most definite; while the influence of one disturbing principle on another may be most clearly traced in other cases as a neutralizing influence, one influence reacting upon the other.
We have at hand many instances of this kind for illustration. Alcohol and tobacco are the most ready examples. In the alcohols, whichever one of the family of alcohols we may take, from the least dangerous wood-spirit, through the more dangerous grain-spirit, up to the much more dangerous potato-spirit, there is one agency at work, a hydrocarbon radical, methyl, ethyl, amyl, according to the alcohol used, which, with different degrees of intensity, plays the same part, producing similar series of phenomena. In tobacco we have a less decisively known combination at work, but we have in that combination the element nitrogen, the introduction of which causes a new development of nervous phenomena, the analogous action of which can be traced through some other complex organic compounds containing the same element—nitrogen. In chloroform, again, we have a hydrocarbon radical playing nearly the same part as the radical methyl of methylic alcohol, but with chlorine interposing to modify the simple narcotic action of the radical, and greatly to increase the danger of the compound in its effect on the living body. Physiological research has not yet reached, by vital analysis of action, a perfection of knowledge on the subject now in hand. Such analysis is yet in its early days. At the same time a general line of research has been made out, and some results have been obtained which are of direct practical value. Other facts have also been elicited which at first sight are surprising, but which lose their singularity when they are correlated with pure chemical physical demonstrations. I found, for example, in one of my researches, that two chemical substances which are isomeric in constitution—that is to say, are composed of the same elementary forms in the same proportions, but under different arrangement—produce entirely different phenomena on the animal body. These isomeric substances are the formiate of ethyl and the acetate of methyl.
The agents used by man for his dreamy delights have thus a varied influence on his nature. They are often rudely classed together as luxuries; but the luxuriousness which they foster may be fathoms wide until they so far interfere with vital function as to reduce its activity in a notable degree. Then there is something in common between them, just as there is something in common when, being carried a little further, they stop life altogether.
For this is interesting respecting them, in the most potent sense. They all kill when we let them have full play. This is obviously the reason why they are called toxicants and intoxicants. They bear resemblance in action to the poison which once in the history of a past civilization sped on the tip of an arrow from a discharged bow.
The toxicants have variation of action in their early stages. Alcohols excite the mind and quicken the pulses before they depress. Opium excites before it depresses. Tobacco does not in the strict sense excite, but depresses and soothes from the first, so that there are stages, which some persons always feel, when alcohol is antidotal to tobacco. Among those persons who are total abstainers from alcohol few are found who can bear tobacco in the most moderate use of it. Under tobacco the heart seems rapidly to run down in power, and alcohol is called for to whip it up again, also as it seems. The fact is, that the heart is not the organ primarily concerned at all, but the minute vessels at the termination of the arterial circuit. These minute vessels are under a nervous influence by which the passage of blood through them is regulated, and which influence is readily modified by very refined causes acting through the organic or emotional nervous centers. The effect of tobacco on these minute vessels, through the nervous system, is to cause contraction of them as a primary fact, so that the face of the person affected becomes pale and the surface of the body cold, while the heart labors to force on the supply of blood until its own vascular system comes under the influence: then the stomach involuntarily contracts, and, after a time, the voluntary muscles, deprived of blood, convulse tremulously, or pass into active convulsions, as in tetanus. Alcohol, on the other hand, through its influence on nervous functions, relaxes the vessels of the minute circulation, sets free the heart, reduces the muscular power, and in every particular counteracts the tobacco. When a person receives a stun, or is shocked by some intelligence, or sight, or sound, that thereby stuns him, so that, like Hamlet, he is bechilled
"Almost to jelly by the act of fear,
Stands dumb and speaks not,"
he is for the moment in the same state as the man who first tries to smoke tobacco, and who, with pallid face, cold surface, and reeling brain, is to his sense and feeling stricken with all but mortal suffering and prostration. In each of these cases alcohol, for a moment, acts as an antidote not necessarily as the best antidote, but as a fair one. When, therefore, we see a man smoking and drinking, quaffing off the cup of wine or spirit to quiet the qualm which would otherwise be inflicted by the fumes of the cigar or the pipe, we really observe the facts of a most excellently though innocently devised physiological experiment on a living animal. The man, unconsciously to his knowledge, if not to his sensation—unless he be a physiologist—is inducing a balance in the tension of his arterial circuit.
In process of time the nervous system, becoming accustomed to these influences, one or both, in a certain degree tolerates them, for a period. The tolerance while it lasts is an advantage to the habit, and, if the habit were a necessity, it would be a blessing. But the advantage is not permanent. In the end the nutrition of the organic parts which are under the influence of the same nervous regulation is sure to suffer, and in many organizations to suffer rapidly and fatally.
It is probable, if not as yet provable, that all the agents named above produce their specific effect by the influence they exert over the automatic, self-regulating nervous function. In my researches on the action of some substances on the minute circulation, I have been able to differentiate their action by this general rule. The alcohols, the lighter alcohols, including common alcohol, relax the vessels; nicotine constringes; chloroform, by virtue of the chlorine in its composition, constringes; opium relaxes, then constringes; ether relaxes; absinthe, after a time, constringes; chloral hydrate first constringes, and afterward relaxes. From these differences of action the differences of phenomena in the persons affected are explainable. In like manner the ultimate deleterious effects of these agents on the nutrition of the body are explainable. It is a necessary result, for example, that under the long-continued use of alcohol the constantly relaxed and congested vessels should assume a new character and local function; that the parts depending on them for their supplies of blood should be changed from the natural structure to unnatural but definable, and now well-understood conditions of disease. It is an equally necessary result that under the continued influence of opium the constantly constringed vessels should assume a new local function; that nutrition should be arrested in the parts which those vessels supply with blood; and that the shrunken, impoverished body of the confirmed opium-eater should be an outward and visible sign of the internal changes which are being so assiduously and determinately carried into effect by the narcotic.
When these facts respecting the direct physical action of various toxical agents on the body, through the line of the involuntary nervous system, are understood, they connect, through the same direction, the effects of more refined and much less definable influences. They show how psychological phases are ever at hand to modify nutritive changes: how grief, which shocks and dissevers the organic nervous supply, affects the animal life so deleteriously, exciting and reducing, and sometimes in part disabling altogether parts of the organic nervous track. They indicate how an equable nervous current is conducive to permanent nutritive activity and health, and show physiologically that to laugh and grow fat is after all a mechanical proposition. I must not, however, be tempted away into an inviting field of observation, in which the physical and the metaphysical so neatly blend.
It is worthy of remark that the action of the different toxicants to which I am directing attention, and which are in most common use among members of the human family, have in some cases a similar action, and in other cases a dissimilar action on the members of the lower creation. The alcohols appear to possess a toxical influence throughout all the domain of living animal beings. I can find no animals that escape the immediate action of the alcohols, or the remote effects which occur when the changes excited by the alcohols are often repeated. All our domestic animals come quickly under the ban. Birds and fishes do the same. Chloroform, chloral hydrate, and absinthe seem to exert a similar wide range of action. Tobacco is not so extended in its range. There are animals that can take with perfect impunity a dose of tobacco which would poison three or four men. The goat is an animal which can resist the noxious, but to it innoxious, weed.
Opium can be resisted by certain animals with equal readiness. A pigeon will practically live on opium. A pigeon will swallow with impunity as much solid opium as would throw twelve adult men into the deepest narcotism. Indeed, it is not correct to say that to pigeons opium is in any sense a poison.
The reasons for these exceptions are not clearly made out. The probability is, that the animals which take the intoxicants with so much impunity produce some form of decomposition of the agent in their own bodies, by which the active alkaloidal substance is rendered neutral in effect, or, at all events, is much neutralized.
There is a fact of singular interest in relation to the intoxicants I have now described or named, and which before I proceed further should be carefully noticed. The fact is this: That when the agents produce a definite effect upon a living body, whether it be a human body or the body of an animal that possesses desires and likings, there is caused in that body, after a number of times of practice, a craving or desire for the agent that produced the effect. In man this is so marked that the most repugnant and painful of lessons connected with the first subjection to the agent is soon forgotten in the acquired after-sense of craving or desire. It really matters little which of the intoxicants it is that is learned to be craved for; the craving for it will continue when it has struck an abiding impression. We know this fact well from the wide experience that has been gained of it in the cases of alcohol, tobacco, opium, chloral, hasheesh, absinthe, and arsenic. More incongruous things could scarcely be; incongruous to the senses, to the sensibilities, to the methods of taking, to the result of them; yet the craving for any one of them as it is may be established. The devotee to one will laugh at the devotee to another; each one will consider the other almost insane, and yet each will follow his own course.
Still more curious is it that the substances craved for, which lie quite outside the natural wants of healthy life, may be extended to any number. There is in truth hardly a substance to which the craving may not cling. The distinguished Dr. Huxham had under his observation a man who, after a little practice in the habit of taking it, had a craving for the salt now called bicarbonate of ammonia. The man chewed this salt and swallowed it in the same way as he might have swallowed peppermint lozenges. The effect of the salt was to produce extreme fluidity of the blood of the man, so that he became scorbutic, and to cause loosening of his teeth. It also reduced his strength, and even placed his life in jeopardy; and yet his craving for the ammonia remained unappeased until his danger was so great that the noxious thing had to be withheld altogether. The great Sir Humphry Davy gives another, and it may be still more remarkable, experience in relation to himself. When he was making his wonderful researches with nitrous-oxide gas, he commenced, at first for the mere sake of experiment, to inhale the gas in free quantities. By this process of inhalation he obtained the most delicious of visions. Space seemed to him illimitable, and time extended infinitely, so that coming out of one of these trances he exclaimed: "Nothing exists but thoughts; the universe is composed of impressions, ideas, pleasures, and pains!" In course of time Davy, by the frequent repetition of the process of inhalation, became so infatuated that he could not look at a gasholder, could not look at a person breathing—I am using his own description—without experiencing the urgent sense of desire to once more imbibe his favorite gaseous nectar, and revel in his induced and artificial dreams. How closely this confession runs, even from the pen of a philosopher, to similar confessions made by many who are not philosophers, respecting another purely chemical intoxicant which is more generally known than Sir Humphry's gas, I need not stay to explain.
An experience, closely allied to the above, occurred to a scientific friend of mine in relation to another intoxicant—namely, chloroform. This gentleman, commencing like Sir Humphry with the inhalation of chloroform for purposes of experiment, at last began daily to inhale a certain measured quantity. In a few days he increased the quantity, and at last discovered, from the intervals of time which elapsed after he commenced each inhalation, that he must have gone off into deep sleep and so have forgotten to note the passage of time. At first the sense of desire to repeat the inhalation alarmed him greatly, but soon the desire overcame all sense of fear, and at last he became a complete devotee to the practice. A break-down in his health led him to communicate his position to his friends, and by the earnest advice and warning of one of them he did at last resolve to abstain altogether. It was a very difficult fight, the odor of the vapor whenever he was near to it recalling most keenly the old desire, and even four years elapsed before he felt himself fully emancipated from the dangerous habit.
The craving attaches itself to other substances than I have hitherto named. I have known it connected with that most nauseous of all medicines, asafœtida; I have known it strongly attach itself to another medicine, valerian; and once I knew it attach itself to turpentine. My learned and very good friend the late Dr. Willis, of Barnes, had a patient who acquired the craving for common wood or methylated spirit; and there are many who have acquired a liking for spirit that is flavored or more than flavored with fusel-oil.
The readiness with which mankind will attach themselves to varied cravings is shown again and on a comparatively large scale in the north of Ireland. In a district there, of which Draper's Town is the center, the eminent Father Mathew labored in his lifetime with such magical effect that he practically converted the whole district to sobriety. A little after his time, and when the influence of his work was fading away, a person came into the district and introduced a new beverage or drink which was not whisky, which was not strong drink, and which, it was said, would do no harm. The bait took, and for over thirty years there has existed in the place I have named a generation or two of ether-drinkers. I have visited this place recently and found the habit still in progress. The ether-drinker tosses off his two or three ounces of common ether, as another man tosses off gin or whisky. He passes rapidly into a state of quick excitement and intoxication, is often senseless for a brief period, and then rapidly regains the sober state. He suffers less from this process in the way of organic disease than he would from a similar number of intoxications from alcohol; but he gains, as he would from alcohol, the same intense craving, and the craving presents a similar automatic and periodical rule as has been observed in relation to the habitual employment of other active and enticing poisonous compounds.
The nature of these cravings is not more singular than their intensity, when once they have been acquired. The most practiced craver can rarely succeed in explaining upon what the craving really depends. It is an indefinable desire. It is neither thirst, nor hunger, nor pleasure, nor reasonable want. It is rather like a wish to be relieved for the moment of some indescribable sense of pain or discomfort. It is often periodical in its occurrence, and it can, I believe, always be made perfectly periodical, a fact which connects it very closely with the work of the organic nervous system. In a word, in the confirmed craver the work of the organic nervous system, which is singularly periodical and rhythmical in the natural state, is, by these agents, turned into a new direction, and is made to take on a new action which in steady form repeats itself. I have in my house an eight-day clock which, though a century old, does good and faithful work, except at two times in the twenty-four hours, when it goes periodically astray. From some little twist or wear in the machinery, it stops for a moment in the act of striking at one particular stroke of the bell, and on listening to it it seems as if the striking had concluded. Then it strikes feebly and goes on again all right. The working of the involuntary nervous system in health is as automatic and regular as the working of the timepiece; damaged, it is as systematically deranged at particular periods.
The injury from intoxicants, after the first automatic derangement has been established by them, is not to be measured altogether by the first and usual derangement. Unfortunately, the action of the intoxicant extends beyond the mere effect of the craving that springs from it, and involves in its evils structural parts of the animal body. The nutrition of the degraded structures, the sense of muscular and mental fatigue is soon rendered easy of development; and, pari passu, the mind, seeking for aid in the influences it likes, finds a supposed aid in the intoxicant. It takes the destructive agent more frequently, thereby establishing a more frequent periodicity of desire, and a more earnest craving. By these combined influences, as is so commonly observed in the intemperate from alcohol, the craving increases as the animal powers decline, and the tendency to death is vastly quickened in its course. To ordinary comprehension, in these instances, the craving and the sinking are the same acts. They become so at last in effect, but their beginnings are quite distinct, and they are, in the strictest expression of fact, distinct phenomena even to the end.
The craving for these intoxicants, so strong in the habituated among men, is not confined to human kind. The beast that can be brought to taste these agents, and that can be affected by them, can be equally well taught to crave for them, and to look out for them also with automatic and periodical precision. I know of no domestic animal that can not be trained to look out for these agents when the training is conducted with skill and with determination. Like young children, and those persons of later life who have never tasted the agents in any form, nor experienced the sensations which come from them, the lower animals reject them at first, strive against them, and evidently are much disquieted and perplexed by the results which follow their use. But to err is inhuman as well as human, and so the beasts that perish, even they err and learn to like it. In the beast as in the man, the train of events follows the same course. The craving becomes connected almost immediately with deterioration, and at last the two conditions of desire and decay are spun into the same woof, and appear as the same substance.—Contemporary Review.
