It is to these laws of Physical Life, to Physiology, that I wish to call your attention in this lecture. Time would fail me, if I were to attempt to explain all of them; for a full treatise upon this subject usually fills one volume at least, generally more than one. But I shall only endeavor to explain a few of the laws, and those few, in regard to which we have some responsibility. I shall therefore confine myself to the subjects of the digestive system and digestion, the lungs and respirations, the skin and its functions, the locomotive system, the brain and nervous system, their method of operations, and their connections with, and dependence upon external nature; their dependence upon our volitions, and our duties concerning them. It is also my purpose to show the beautiful and happy consequences of health, and vigor, and protracted life, that follow the faithful obedience to these laws; and, on the other hand, the melancholy consequences of pain and weakness, of sickness and premature death that follow from our neglect and disregard of them.

But here I may be asked, What is this Physiology - what are these laws of Physical Life to us? We take life as we find it, and meet death when it comes. We eat, and drink, and labor; we breathe and think; we clothe and shelter our bodies, and enjoy the world as long as life lasts, and of what use is it to us to learn the way that food digests, and that air purifies the blood, or the effects of clothing, exercise, and mental labor upon the body? We know that few can escape sickness, and that death is the common and inevitable lot of mankind. And of what

avail will the knowledge of Physiology be to prevent the one, or to ward off or postpone the other?

This is not a rare doubt, nor is it confined to a few of the uneducated. It pervades all ranks, the learned and the simple indulge in it. Its woful consequences are manifested throughout the whole world. But it is founded upon the ignorance of those very laws, which are neither understood, nor believed, nor obeyed.

There is a common, perhaps a general notion, that diseases come from without, and not from within; that they come down from Heaven, or arise up from the ground; that they and death are the messengers of Providence, and have nothing to do with the condition of our organs, nor with our faithfulness or unfaithfulness to the laws of our members.

A cursory view of the five organs and functions before spoken of, and of their relation to external nature, and our duty in respect to them, will show the fallacy of these notions, and convince us that our health and our strength are placed, by a generous Providence, in our hands to keep and sustain, and that we are truly responsible for their full and protracted maintenance.

All the works of the Creator are the results of infinite wisdom and of infinite goodness. There is a beauty and also a harmony running through them. Every one of these works is complete and perfect in itself, and perfectly adapted to its station in the universe. It is fitted to the circumstances amidst which God has placed it; to the elements that float about

it, and is capable of effecting the purposes for which it was designed.

The human frame, as it comes from the hands of the Creator, is a perfect, self-sustaining, vital machine. It is composed of many organs of various kinds, which perform various functions, and effect different purposes; yet all of these so coöperate as to produce one grand result, which is Life.

In this collection of organs there is no redundance; there is not one too many, neither is there any one wanting. Each is made exactly of the due shape and size; it is placed in precisely the situation, and is endowed with just the powers needful for the performance of its duties. Each one performs its own work, and no other. Each one acts independently in its own sphere, yet is dependent upon all the rest for its power. No one is strong, if any of the others are weak. No one acts with its full energy, unless the others are also in active and undisturbed operation.

He cannot breathe freely, unless he digest well; nor can he digest well, unless he have muscular power and muscular motion; nor can he have muscular power, unless the skin perform its functions faithfully. For any one organ to be well, all must be well; and whenever any one suffers and is weak, the others sympathise with it, and are also weak.

Some of these organs depend upon the external elements; all of them are more or less under the control of man; and so far as they are under his control, they are submitted to his direction, for good or for evil.

MAN RESPONSIBLE FOR THE USE OF HIS ORGANS.

The generous and provident Creator has given to man all the organs and vital machinery necessary for carrying on the operations of life. But he has left it to man, to set and to keep some of these in motion.

He has supplied man, or has given to him the means and the power of supplying himself, with all the materials and the elements upon which these organs are to operate. All directly or indirectly are supplied to us, and nothing is wanting for the support of our lives.

We are supplied with the digestive apparatus, by which dead food is to be converted into blood and flesh; and the same hand has furnished us with the elementary principles out of which that food is to be made. But it is assigned to us to select that food, to determine its quantity and quality, the times and the manner of eating, and to adapt the whole to the peculiarities of our individual constitutions.

We have given us lungs to breathe, and the air to enter them; but it is left to us to see that air is always pure, and fitted to effect the due changes in the blood.

We receive our skins from the Creator's hand, but we are to make and adapt the clothing and protection to their wants. We are to give them the needful cleaning and friction.

The muscles and the rest of the locomotive apparatus are made to our hands; but how much or how little these shall be exercised, is left to our control.

The brain and the nervous system are the creation of God. But how, and to what degree these shall be worked, to what purposes they shall be applied, is left to our discretion and our volition to determine.

Thus we see, that in carrying on these functions of life, we are the coöperators with the Creator. He has done one part towards this work, and left us to do the rest; and he has put into our hands the means and the powers to do what he has required of us.

What God has done for us is well done. So far nothing is deficient, and nothing is redundant. What we do, is done well or ill according to the degree of our intelligence, of our knowledge of the organs with which, and of the material upon which they are to operate, and according to the conscientious faithfulness, which we apply to our part of the work.

Seeing then that we are the co-workers with the Creator in the work of sustaining life, it will be our first duty to learn what has been done, and what is left for us to do; to know the nature, powers and wants of our bodily organs; the purposes to which they can best be applied, and their capacity of endurance. We should also ascertain the nature and fitness of the material, upon which they are to operate. Without this knowledge we may err and stumble; we may supply our organs with improper material, or apply them to improper purposes; we may thus create weakness instead of strength, and disease instead of health.