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sity of Toronto around the world. I have had great pleasure in going through his new building with Professor Ellis, and in recognizing that a chemist, whatever may be the fate of prophets, is not without honor in his own country.

I also rejoice in your splendid new Medical Building, and I envy the freshman of today, who comes filled with the earnest intention to do his work well, and who, under these favorable conditions, in the wellequipped modern laboratories, with such able masters to direct, begins the study of the beneficent science of medicine. I was greatly rejoiced on reading in the papers this morning of the munificent gifts that have been made for the new university hospital. Surely the people of Toronto are both wise and generous. He who aids in building a hospital, where human suffering may be relieved, is a practical Christian, whatever his theological dogma may be. We know not whence we came, nor can we name the country to which we journey, but we do know that the burdens placed upon the shoulders of those who travel along life's highway are not equally distributed, and he who helps his fellow-man, who is growing faint, serves his God. There is an old legend concerning the origin of the medical profession, which I may, I hope, be permitted to repeat. It runs thus: In the olden days when the world was yet young, a young Hindoo prince, who had all the world

a could give, entered a temple and, prostrating himself before the image of Buddha, besought his god to instruct him in the ways of righteousness. His prayer ended, he felt upon his shoulder a hand as light as that of a child, and a voice as sweet as that of an angel asked, “Wouldst thou most acceptably serve thy God? If this be thy desire, go forth and serve thy fellow-men," and the prince went forth, the first physician to walk among men.

My visit is not without its tinge of sadness. I miss several faces that were familiar to this campus fifteen years ago. Of two of these I must be permitted to say a few words. There was a sweet-mannered man, gentle in voice and kind even in reprimand, an eminent ethnologist, an able historian, whose memory has always been to me a charming recollection. Such a man was Sir Daniel Wilson. The other was a professional brother, whose life was a help to those of his own generation and an inspiration to the young. Such a man was the late Doctor Graham, of this city and university.

I have decided to briefly discuss “Some New Conceptions of the Living Cell: Its Chemical Structure and Its Functions." No one can question the importance of this subject, involving, as it does, biological problems, which lie at the foundation of all our conceptions and theories concerning cellular life and cellular activity.

To start ab initio, the cell is made up of matter, and the newer views on matter must be taken into consideration in formulating a conception of the cell. When matter becomes endowed with life it does not cease to be matter; it does not lose its inherent properties; it is not released from the laws that govern its structure, its attractions, and its

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motions. In studying the organized cell of living thing, whether vegetable or animal, it should always be borne in mind that it is material in composition and subject to the fundamental laws that govern matter, and possessed of those properties essential to matter. In order that this point, so essential to a proper understanding of the subject, should be thoroughly appreciated, it may be best to recall some of the prop erties of matter as taught by the most advanced science of the day.

Tait says: "Matter is that which can be perceived by the senses, or is that which can be acted upon by or can exert force.” Since force is the result of motion, we may say that anything and everything that moves or can be moved, or whose position in space may be changed is matter. There are many forms of matter that cannot be seen or felt, and can be recognized only by their motions.

Matter is indestructible; it may be successively solid, liquid and gas, but in undergoing these changes it neither gains nor loses. It has always been, and it always will be. It is without beginning and will be without end. Matter consists of infinitely small particles, called atoms. According to the computation of Lord Kelvin, the diameter of an atom is not greater than a 1-50,000,000 of an inch; however, all atoms are not of the same size or weight. When like atoms combine they form .chemical elements, of which about seventy are known. The hydrogen atom is the lightest of all known elements, and it therefore is taken as the base or standard in the determination of atomic weights. When unlike atoms combine, chemical compounds are formed, and the number of these is beyond computation. It was supposed, until the discovery and study of radium, that one chemical element is never converted into another, and consequently that the number of kinds of atoms is fixed and unchangeable. However, it has been found that the x-rays of radium consist of most minute particles, which, when confined in glass, condense and form another element, helium. With this demonstration of the formation of one element from another it is within the range of sanity to suppose that all the elements have been developed from a primordial ancestor, probably from the universal ether which pervades all space. Nothing has been created; everything has grown. Even silver, iron, and other metals came into existence by being cast off from some common ancestral element. The atomic weight of radium is 225 and that of helium 2.02. It would seem from this that an atom of the former breaks up into about one hundred atoms of the latter, and in this way a new element is born, although in this case it is probable that the mother atom is split into two or more kinds. It will be seen from this that even atoms may be split up. Indeed, there are reasons for believing that the hydrogen atom consists of a nuclear ion about which some seven hundred particles or electrons revolve, and an atom of mercury is believed to consist of not less than one hundred thousand electrons. Atoms and electrons are in constant motion, and 50 small are they that the distances between them may be relatively as great as those between the planets of the solar system. The living cell is composed of molecules, made up of atoms, composed of electrons that are in constant and systematic motion, and may be compared to a group of stars with attendant suns, each of which is surrounded by its own planets. A molecule of albumin is of like composition.

Another property of matter is that it is gravitative. Every particle of matter attracts every other particle. When this attraction is manifest between masses it is called gravitation; between molecules, it is called cohesion or adhesion, as the molecules held together are alike or unlike; between atoms it is known as chemical affinity or chemism.

Still another property of matter is inertia, by which term we indicate the inability of matter to change either its rate or direction of motion without being acted upon by other matter. It is of great importance that this property of matter be held in mind in the study of cellular chemistry, and the proper mental picture of a cell molecule represents each of the atoms in the molecule, and each electron in each atom moving each about its centre and each at a definite rate. If such a cell molecule could be cut off permanently from the disturbing influence of other matter, its atoms and electrons would continue the same motions, unchanged in direction or rate, throughout eternity, but, as we shall later see, it would be impossible for living matter to continue to live apart from other matter. Within the living cell molecule change in number, kind, and arrangement of atoms is constant; and the direction and rate of the motion of the atoms are also susceptible to the influence of other matter and are of constant occurrence. Whole groups of atoms are physiologically being dropped from the cellular molecule and being replaced by other groups split off from the pabulum upon which the cell feeds. In this way the cell renews itself and keeps itself supplied with energy.

Some of the most noted physicists are inclined to the belief that matter is made up of electric charges, but recognize that this is not a demonstrated fact as yet, and speak with caution. Lodge says: “There may possibly be two different kinds of inertia, which exactly simulate each other, one electrical and the other material; and those who hold this as a reasonable possibility are careful to speak of electrons as 'corpuscles,' meaning charged particles of matter of extremely small size, much smaller than an atom, consisting of a definite electric charge and an unknown material nucleus; which nucleus, as they recognize, but have not yet finally proved, may quite possibly be zero.

The only essential and constant difference between living and nonliving matter is that within the molecules of the former there is constant metabolism, while in the latter no such process occurs. We are to conceive of the living molecule as made up of numerous atoms and each atom surrounded by its electrons: atoms and electrons in ceaseless motion, and groups of atoms being constantly cast out of the molecule and replaced by new groups split off from matter outside the molecule. As soon as a molecule becomes the seat of assimilation and excretion, it is no longer dead, it lives. As a result of assimilation

it acquires the property of building up its own tissue; then polymerization follows and reproduction in its simplest form begins. The one phenomenon always manifested by living matter, and never exhibited by nonliving matter, is metabolism. Verworm says: "Vital motion, metabolism, is a complex motion very strongly characterizing the living organism; it consists in the continual self-decomposition of living substance, the giving off to the outside of the decomposition products, and, in return, the taking in from the outside of certain substances which give to the organism the material with which to regenerate itself and grow by the formation of similar groups of atoms, that is, by polymerization. This is characteristic of all living substance."

I have promised to give you some of the new conceptions of the living cell, and yet I must admit that Aristotle apparently recognized that metabolism is the one characteristic of living matter, for he says: "Life is the assemblage of the operations of nutrition, growth and destruction.” Of course, this Greek philosopher did not know about cells, molecules, atoms and electrons what is today known, but it must be acknowledged that he had a clear conception of the most essential characteristics of living matter. Herbert Spencer has given three definitions of life, and either may be applied to the conception which I am trying to present to you. The first is : "Life is the coördination I

The coördination between assimilation and excretion is certainly essential to life, and failure of this coördination leads to death. The second is probably the best definition of life ever given, and fits our conception perfectly. It is : "Life is the definite combination of heterogeneous changes, both simultaneous and successive, in correspondence with external coexistences and sequences.” The third is practically the same as the second, expressed in simpler terms, but in my opinion not so satisfactorily. It reads: "Life is the continuous adjustment of internal relations to external relations." Matter is alive when it feeds and excretes. Crystals grow and in a sense they multiply, but their growth is not intramolecular, it is by accretion. The living molecule not only absorbs, it assimilates. It chemically alters what it absorbs. The atomic groups taken into the living molecule enter into new combinations. The living molecule is not stable, but is highly labile. Its composition is never constant and it is never in a condition of equilibrium. There is a constant reaction between the living molecule and other molecules. Apart from other matter it could not exist. There is a constant interchange of atoms between it and other molecules. A condition best designated as latent life may exist without interchange of atoms between molecules. This is seen in spores, seeds and ova. Matter existing in this form may be awakened into activity by proper stimuli; active life begins with the interchange of atoms.

Why is there this constant atomic group interchange between the living molecule and outside matter? It is for the purpose of supplying the living molecule with energy. Allen has so ably expressed this

fact that I make the following quotation: “The most prominent and perhaps most fundamental phenomenon of life is what may be described as the energy traffic or the function of trading in energy. The chief physical function of living matter seems to consist in absorbing energy, storing it in a higher potential state, and afterwards partially expending it in the kinetic or active form. We find in living matter a peculiar proneness to change its composition under the stimulus of slight changes in the energy-equilibrium between itself and its surroundings, energy being readily absorbed and readily dispersed. The absorption of energy coincides with deoxidation and the building of large molecules ; conversely the dispersion of energy coincides with oxidation and the disruption of the large molecules. The building of these large molecules is always accomplished by slow steps; but when formed, the said molecules are very unstable, irritable, or in modern phrase, labile. They may break down by degrees in some instances; in others their structure may be so precarious as to collapse on the slightest disturbance."

“The lability of such a molecule may be compared to that of a house of cards, which can be taken to pieces, card by card, or may collapse at once. But the word lability is applied, not only to de-structive, but also to con-structive instability. The molecules of living substance are prone to constructive as well as destructive changes; but, as in the house of cards, the constructive changes are the most gradual; and as the structure grows more complex, construction becomes more difficult, and collapse is more imminent. It should be distinctly understood, however, that it is not the mere size of the molecules that makes them labile, but rather the manner in which they are linked together, and the amount of potential energy which is included in the molecule.”

It is probable that in the absorption of energy by the living molecule, oxygen is relieved from its combination with carbon or hydrogen and is attached to nitrogen, while in the liberation of energy the reverse takes place. Nitrogen and phosphorus, sometimes with iron and possibly manganese, seem to be, as it were, the master elements within the living molecule. It is by virtue of their chemism that groups are torn from extracellular matter, taken into the living molecule and assimilated by an atomic rearrangement; and furthermore, it is on account of the lability of the compound thus formed that potential energy is converted into kinetic and cell work is accomplished.

The question of the origin of life on this world has been ably discussed by eminent chemists, physicists and biologists. The cosmozoa theory proposed by Richter holds that cellular life has always existed, and has been transferred from one planet to another by meteors and cosmic dust. Richter says: Ounne vivum ab aeternitate e cellula.Helmholtz and Lord Kelvin have pronounced this theory not unscientific, and the former makes the following statement: “Meteoric stones sometimes contain hydrocarbon compounds; the intrinsic light of the

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