must we comprehend their meaning, but our intellects and sentiments must be disciplined into the habit of actual performance. The work of acquiring and practically using scientific information concerning the natural world, its qualities, and their relations, is to the intellect and sentiments what dancing is to the muscles-it invigorates them; and as it is from them that obedience to the natural laws must spring, the exercise renders it easy and delightful.

It is only by comprehending the causes on which consequences depend that we become thoroughly impressed with the invariableness of the physical and the organic laws, acquire confidence in and respect for them, and fairly endeavour to accommodate our conduct to their operation. The human faculties are spontaneously active, and desire gratification; but the intellect must have fixed data on which to reason. A man in whom the faculties of constructiveness and weight are powerful will naturally betake himself to constructing machinery; but if he be ignorant of the principles of mechanical science, he will not direct his efforts to such important ends, nor attain them with so much success, as if his intellect had been stored with this kind of knowledge. In like manner, a man may compose music by the impulses of the faculties of tune and time; but as there are immutable laws of harmony, he will not compose so correctly and in such good taste if he be ignorant of them as he would do if he knew them.

In every art and science there are principles referable solely to the constitution of nature, which admit of countless applications. By following the laws of harmony, a musician may produce gay, grave, solemn, or ludicrous tunes, but he will never produce one good piece by violating them. While the farmers near Edinburgh allowed stagnant pools to deface their fields, some seasons would be more healthy than others; and while the cause of disease was unsuspected, this would confirm them in the notion that health and sickness were dispensed by an over-ruling Providence on inscrutable principles. But the moment the cause was known, it would be found that the most healthy seasons were those which were cold and dry, and the most. sickly those which were warm and moist. They would then discover that the salubrity of one year and the unwholesomeness of another were clearly referable to one principle; and after perceiving this truth, they would be more strongly

prompted to apply the remedy, and also rendered morally and intellectually more capable of doing so. If some intelligent friend had merely advised them to drain their fields and remove their dunghills, they probably would not have complied; but whenever their intellects were led to the perception that nature was so constituted that the evil would continue until they acted in this manner, the improvement would be promptly effected.

The late Dr. Robert Macnish, of Glasgow, favoured me with the following communication, suggested by a perusal of the second edition of the present work:-" On four several occasions I have nearly lost my life from infringing the organic laws. When a lad of fifteen, I brought on, by excessive study, a brain-fever which nearly killed me; at the age of nineteen I had an attack of peritonitis,* occasioned by violent efforts in wrestling and leaping; while in France, nine years ago, I was laid up with pneumonia,† brought on by dissecting in the great galleries of La Pitié with my hat and coat off in the month of December, the windows next to me being constantly open; and in 1829 I had a dreadful fever, occasioned by walking home from a party at which I had been dancing, on an exceedingly cold inorning, without a cloak or great coat. I was for four months on my back, and did not recover perfectly for more than eighteen months.

"All these evils were entirely of my own creating, and arose from a foolish violation of laws which every sensible man ought to observe and regulate himself by. Indeed, I have always thought and your book confirms me more fully in the sentiment-that by proper attention, crime and discase and misery of every sort could, in a much greater measure than is generally believed, be banished from the earth, and that the true method of doing so is to instruct people in the laws which govern their own frame." In 1837 Dr. Macnish was cut off by typhus fever in the prime of life.

The following case, also illustrative of the points under consideration, is one which I had too good an opportunity of observing in all its stages.

A person in whom it was my duty as well as pleasure to be greatly interested resolved to carry Mr. Robert Owen's

* Inflammation of the lining membrane of the abdomen.

† Inflammation of the lungs.

views into practical effect, and set on foot an establishment on his principles at Orbiston, in Lanarkshire. The labour and anxiety which he underwent at the commencement of the undertaking gradually impaired an excellent constitution; and, without perceiving the change, he, by way of setting an example of industry, took to digging with the spade, and actually wrought for fourteen days at this occupation, although previously unaccustomed to labour. This produced hæmoptysis, or spitting of blood. Being now unable for such severe exertion, he gave up his whole time to directing and instructing the people-about 250 in number -and for two or three weeks spoke the whole day, the effusion of blood from his lungs continuing. Nature sank rapidly under this irrational treatment, and at last he came to Edinburgh for medical advice.

When the structure and uses of his lungs were explained to him, he saw that his treatment of them had been equally injudicious as if he had thrown lime or dust into his eyes after inflammation. He was struck with the extent and consequences of his ignorance, and exclaimed, "How greatly should I have been benefited if one month of the five years which I was forced to spend in a vain attempt to acquire the Latin language had been dedicated to conveying to me information concerning the structure of my body, and the causes that preserve and impair its functions!"

He had departed too widely from the organic laws to admit of an easy return: he was seized with inflammation of the lungs, and with great difficulty survived that attack; but it impaired his constitution so grievously, that he died after a lingering illness of eleven months. He acknowledged, however, even in his severest pain, that he suffered under a just law. The lungs, he perceived, were of prime importance to life, and a motive to their proper treatment was provided by instituting the painful consequences which followed from neglecting the conditions requisite to their health. Had he given them rest, and returned to obedience to the organic law at the first intimation of departure from it, the way to recovery was open; but in ignorance, he persevered for weeks in direct opposition to the law, till the melancholy result ensued.

This last case affords a striking illustration of a principle already noticed—namely, the independence of the different natural laws, and the necessity of obeying all of them as a condition of safety and enjoyment. The person here

mentioned was deeply engaged in a most benevolent and disinterested experiment for promoting the welfare of his fellow-creatures; and superficial observers would say that this was just an example of the inscrutable doings of Providence, which visited him with sickness, and ultimately with death, in the very midst of his most virtuous exertions. But the institutions of the Creator are wiser than the imaginations of such men. The first condition on which life and all its advantages depend is obedience to the physical and the organic laws. The benevolent Owenite, in his zeal to obey the moral law, neglected these, and suffered the consequences of his omission.

Some hold that it is a question purely of discretion or of prudence to obey or to disobey the physical and the organic laws, and that to attain an important and moral object we are justified in setting them at defiance. But in my

opinion it is impossible to set them at defiance with success: in other words, to escape from the consequences which God has attached to the infringement of them. In cases in which we may be unavoidably ignorant of the natural laws, or be uncertain concerning the limit of our own ability to obey them, we may be morally justifiable in encountering the hazard of an infraction of them in the pursuit of a high and virtuous aim; but we must never lose sight of the fact that if we do miscalculate and infringe them, the merits of our motives will not save us from the appointed consequences.

If we know the laws, it is our duty in every case to obey them as far as we can. A young medical practitioner danced at a ball all night, exhausted his organic system by fatigue, and in this condition, without sleeping and without taking food, proceeded to pay an early visit to a patient labouring under typhus fever. The object was a moral one, and he obeyed the call of professional duty; but what was the consequence? Within twenty-four hours of his visit he was seized with the same fever, and in ten days he died. Who gained by his thus setting the organic laws at defiance at the call of duty? Obviously not the patient, for he never saw him again; not the medical practitioner, for he died; and not society, for it lost a valuable member.

Let me not, however, be misunderstood. I do not teach that in order to avoid infringement of the organic laws every one should fly from a patient affected with a contagious disease. My doctrine is simply this-that in attending such

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a patient, every requisite of the organic laws which tends to diminish susceptibility of infection should be religiously complied with. The midnight dancing, by exhausting the body, prepared it to receive infection, and the want of food and sleep deprived it of a resisting power. If the young man had believed in the natural laws, he would either have avoided the ball, knowing his liability to be called on at all hours to visit patients labouring under dangerous diseases; or have gone home to bed, and requested an unexhausted and well-fortified friend to visit the patient that morning in his place.

The physical and the organic laws, having been instituted by the same God who appointed the moral laws, are not likely to be inconsistent with them, nor are they so unimportant that we may justifiably treat them with disregard, according to our own short-sighted views either of expediency or of duty. If it were possible to evade the consequences of one law by obeying another, the whole field of Man's existence would be involved in inextricable disorder.

Another case was communicated to me by an actual observer. A gentleman far advanced in years fell into a state of bodily weakness which rendered the constant presence of an attendant necessary. A daughter in whom benevolence and veneration were largely developed devoted herself to this service with ceaseless assiduity. She was his companion for month after month, and year after year --happy in cheering the last days of her respected parent, and knowing no pleasure equal to that of solacing and comforting him. For months in succession she never left the house; her duty became dearer to her the longer she discharged it, till at length her father became the sole object on earth of her feelings and her thoughts. The superficial observer would say that this conduct was admirable, and that she would receive from Heaven a rich reward for such becoming and virtuous devotion.

But Providence rules on other principles. Her enjoyment of mental happiness and vigour depended on the condition of her brain, and her brain was subject to the organic laws. These laws demand, as an indispensable condition of health, exercise in the open air and variety of employment, suited to maintain all the faculties in activity. She neglected the first in her constant attendance in her father's chamber; and she overlooked the second in establishing him as the exclusive object of her regard. The result was that she