tant observations on the white bloodcorpuscles, to which the name of "phagocytes," or "eating cells" has been very generally applied. He has shown, for example, that the vanishing of the tail of the tadpole is really due to the useless structure being eaten away by the phagocytes. The roots of a child's first teeth are similarly disposed of that they may easily drop out and make way for their successors. But the work of the white blood-cells is most certainly focussed in their function of destroying microbes, and of contributing to the healing and repair of wounds and injuries at large. Experiment shows that if the web of a frog's foot be inoculated with microbes, the white blood-cells may be seen to issue forth in numbers from the blood-vessels in the neighborhood of the injury, and attack them. The bacilli or germs can be seen engulfed within the bodies of the phagocytes as a preliminary to their ultimate destruction. When the battle is very fierce, two or more phagocytes will join together, thus rendering mutual aid in the combat against the invaders.

When we study the process familiarly known as "inflammation," we find the most perfect illustration at once of the duties of the white bloodcells and of the new phase and meaning of a common occurrence which are revealed by research. "Inflammation" is a process which follows upon a large variety of injuries, and which marks the onset and course of many diseases, from a scratch on the finger to an inflammation of the lungs. The ancients were very familiar with this process. They categorically summed up its chief symptoms just as we observe them today, in the four words, heat, redness, swelling, and pain. It was long the custom to regard inflammation as constituting a disease in and by itself. To-day we recognize clearly enough that the process can at the most be

described as one introductory to a diseased state, and, what is more to the point, as a process much more nearly related to the action of healing and cure than to that of disease itself. Given a simple scratch, and the phagocytes stimulated by the injury to the tissues will come hurrying to the scene of the accident like ambulance men, eager to assist in the removal of any deleterious matter, and to give their aid in the healing process and in the formation of the new tissue, the production of which will complete the cure. But given a scratch that inoculates the finger with "dirt," which is only another name for microbes, and the nature of inflammation becomes clearer to us. In a few hours the finger will begin to feel painful; its temperature will rise; it will appear red and "inflamed," and it will exhibit swelling. Later on, if we puncture the swelling, we shall find a yellow fluid, which we name "pus," or "matter," escaping from the puncture.

Now, to what are the symptoms of inflammation due? The plain answer is, that they represent the results of a great migration of phagocytes from the blood-vessels, destined to attack. and if possible remove, the infective particles which threaten to do us injury. The inflammation, in this view, is the evidence of a battle being fought in our favor, and often with very long odds against us. If our phagocytes gain a complete victory, we escape the suppuration which we saw to result in the shape of the "festering" finger. If, on the other hand, they sustain defeat. they will fight on, leaving their dead behind. It is the dead white bloodcells, which have fallen in the fray. which constitute the "pus" or "matter" we find in wounds. One cannot summarize this wonderful story more graphically than in the words of Mr. J. Bland Sutton, F.R.C.S., when he says that the story of inflammation should

be likened to a battle "The leucocytes (another name for the white bloodcells) are the defending army, their roads and lines of communication the blood-vessels. Every composite organism maintains a certain proportion of leucocytes as representing its standing army." The body invaded by microbes or other irritants has its telegraph system in the shape of certain nerves, whereby the white blood-cells are called to arms, and, as Mr. Sutton remarks, sometimes recruits arrive in obedience to the call, to the number of twenty or even forty times the normal standard. Then, he continues, “in the conflict the cells die, and often are eaten by their companions; frequently the slaughter is so great that the tissue becomes burdened by the dead bodies of the soldiers in the form of pus, the activity of the cell being testified by the fact that its protoplasm often contains bacilli, &c., in various stages of destruction. These dead cells, like the corpses of soldiers who fall in battle, later become hurtful to the organism they in their lifetime were anxious to protect from harm, for they are fertile sources of septicemia and pyæmia (blood-poisoning) pestilence and scourge so much dreaded by operative surgeons.

the

Such is the story which forms the natural prologue to the history of "Opsonins." For many a day after the publication of Metchnikoff's discoveries regarding the germ-killing power of the phagocytes, it was held that these living cells alone accomplished the duty of disposing of troublesome invaders. Later on, other opinions were advanced to the effect that while the phagocytes did undoubtedly accomplish their work in the direction indicated, they demanded aid to that end from an outside source. This source was indicated and represented by the plasma or blood-fluid itself. The fluid part of the blood had long been known to pos

sess germ-killing properties, but the extent of its powers in this direction had not been duly determined, nor had the important point been settled whether the plasma as a whole or only part thereof aided the white blood-cells in their forays on microbes. Metchnikoff never wavered in his opinion that the phagocytes were, of themselves, and unaided, capable of effecting all that was required in clearing the deck of the living ship of its foes; but it was generally admitted that the true place of the blood-fluid, and the possible part it might play in the germkilling work, were points which deserved close investigation. Researches made prior to the year 1903 gave cause for the belief in the importance of the blood-plasma in whole or in part, but it was in the year just named that very important investigations were undertaken with the view to determining the exact status of the blood-fluid in work of bactericidal kind.

Drs. Wright and Douglas of St. Mary's Hospital, London, undertook a piece of research conducted on lines somewhat different from those on which previous work of this nature had been carried on. They proceeded first of all by the aid of delicate processes to separate the blood-corpuscles from the blood-fluid. The white blood-cells were thus kept in a medium or fluid of neutral kind, while the blood-fluid itself on the other hand was obtained free from its corpuscles. Next in order. an emulsion of certain microbes capable of producing disease was made in a solution of salt. When the phagocytes, alive, of course, in their neutral fluid, were allowed access to the germs they did not attack them. It was as if two contending armies had been brought face to face, waiting to attack, but restrained by some negotiations proceeding between the commanders. The case was at once altered, and the battle began, when the

separated Added to

experimenters brought the blood-fluid into the field. the germs and to the phagocytes, these elements, which had been "spoiling for a fight," joined issue, and the white blood-cells performed their normal work of microbe-baiting. There was but one inference to be drawn from these facts. Clearly, the addition of the blood-fluid supplied some condition or other necessary for the development of the fighting powers of the cells, and such a conclusion forces our mind backwards in time to the recollection of the views already noted, that the phagocytes themselves were not the sole agents concerned in the work of microbe-killing, but that the bloodfluid also exerted a decided influence and effect in the performance of that work.

Our investigators are of opinion that the real source of the power possessed by the blood-fluid or "plasma" is to be sought and found in substances contained therein and called "Opsonins." We can now appreciate the meaning of this term. It is derived from the classic verb for catering, for preparing food, or for providing food. The view taken of opsonic action justifies the use of the word, for it is believed that these substances perform their share of the germ-destroying work, not by urging on or stimulating the phagocytes to the attack, but, on the contrary, by acting on the microbes, by weakening their powers of resistance, and by rendering them the easy prey of the white bloodcells.

The "Opsonins" are carried by the blood-stream everywhere, and it is when they come in contact with any microbe-colonies in the body that they exert their specific action on the germs. It would almost seem as if they partially cooked the microbes, or shall we say stupefied them, in order to render them less effective antagonists of the phagocytes for whom they cater as it were. In this connection

it is very curious to note that Metchnikoff himself, years ago, seems in a measure to have unconsciously anticipated the opsonic theory. We find him telling us that he injected living eggs of a sea-urchin into the body of a transparent sea-slug, known as Phyllirhöe. These eggs were not eaten by the phagocytes of the mollusc, but if boiled eggs of the sea-urchin were introduced the phagocytes quickly seized upon them and devoured them. It would seem as if the boiling acted here after the fashion of the "Opsonins" elsewhere, the experiment with the sea-slug being perhaps more typi cally "opsonic" in the sense of the term "catering for" than that which nature performs on her own account.

The idea that the more active our white blood-cells are, and the more extensive and complete their work, the greater the amount of “Opsonins” present, is one which seems to be founded on a rational basis. This view regards these substances as the real cause of phagocytic activity. That "Opsonins" furthermore appear to possess definite degrees of power seems proved by the observation that a person's blood may contain sufficient to deal with one disease in the way of stimulating the phagocytes to work. while the same quantity would not equal half that required to effect a satisfactory attack on another and different disease.

What has been called the "opsonic index" of a person is the standard, if so we may call it, or measure of his germ-killing power, in so far as the amount of "Opsonins" contained in his blood is concerned. By a technical procedure and calculation the experimenter can compute the opsonic power of a given specimen of blood. An example has been given of a patient who was the subject of frequent attacks of boils, extending over a pe

riod of four years. The infection here was due to the invasion of a wellknown microbe, the Staphylococcus pyogenes. The normal "opsonic index" is given as 1.0, that is the amount of "Opsonins" present in a healthy body; that of the patient was represented by the lessened or abnormal figure 0.5, so that his blood exhibited just half the quantity of "Opsonins" necessary to pave the way for successful phagocytic attack on the germs of his ailment. It is possible to increase the quantity of "Opsonins" in the blood by certain technical procedures, and in the case just noted this was effected with the result of a cure of the troublesome ailment.

Such a statement brings us last of all face to face with the practical, that is, the disease-curing, aspect of the opsonic theory. This aspect is already receiving attention, and the results already attained in the case of tuberculosis are of a significant and hopeful character; and not only so, but in that The Cornhill Magazine.

all-important matter, the diagnosis of disease-a task often of highly difficult nature "Opsonins" are likely to play a prominent part. These matters belong to the technical phases of the subject, and it is sufficient for us simply to know something of these recent investigations which have shown us in a new sense that "the blood is the life." Will the future of science place within medical hands substances derived from the blood itself "Opsonins," which will specifically give our white blood-cells the power to conquer the different grave diseases that attack us? or shall we be shown how, by godly living in a physical sense, we may increase or maintain the opsonic standard of the blood, and thus secure freedom from disease invasion?-who can tell? At the very least, and as the opsonic theory stands to-day on the threshold of its development, it presents us with a new chapter in the romance of Science.

Andrew Wilson, Ph.D., M.B.

I.

In the chilly gray of the summer dawn Murtagh Gilligan was wakened by something skirling and croaking down his chimney. It was an earlyrising jackdaw, which, having with fateful consequences thoroughly roused the reluctant sleeper, flew away out of his story. Murtagh got up at once, and made his way cautiously out of doors, not because he felt any wish to explore his new, hateful surroundings, but merely because it seemed intolerable to lie still and think how far he was from Barnadrum. All the day before he had spent, to his sorrow, in journeying eastward across the width of Ireland. An outside-car at each end, with an interminable train in the space be

tween, had carried him through scenes which he had not the heart to notice, and dusk had blurred everything by the time he neared his destination.

Now as he stood at the little green wooden gate, he looked about him with small curiosity, so firmly was he convinced that in his lost Barnadrum alone could life be worth living. The fact that he had known no other place in his five and twenty years did but strengthen this conviction. He could

not be said to have chosen a propitious moment for his first survey of prejudged Portcormac. It was that trying hour before sunrise when in the lack-lustre twilight everything wears a drearily unreal aspect, meaningless somehow, and yet menacing. Murtagh

saw a flat stretch of tilled land, with a sprinkling of cottages and trees. Close at hand the fields were large and square, divided by low, straight hedges, and mostly filled with cabbages and turnips. "Faix, but it's the quare, ugly, unnathural lookin' little doghole," he said to himself. "I wisht the divil was sailin' away wid the half of it before ever I set eyes on it."

The country he had quitted is partly spread in wide moorlands, and crumpled partly into peaks and glens, so that its wild spaciousness abounds with small sheltering nooks, one of which had been his own and his forefathers' for the dear knows how long between them all. Certainly the accumulated regrets of many generations seemed to weigh upon Murtagh's spirit as his thoughts turned toward the little house under the hill. With more clearness than meets the bodily eye he beheld the fleck of white and brown against the grassy steep, dappled with furze and boulders; it was as if the sweeping slope had receded into a hollow just for the accommodation of the Gilligans' abode. Murtagh, at any rate, felt that he had left the single spot on earth into which he fitted, and to which he belonged by rights. Beyond it the whole world was as unsuitable for a dwelling-place as the lonesome ocean that, not many roods from his door, rounded off everything to the westward with a hazy rim.

And here, by the same token, he descried a few fields off the familiar watery curve, dimly colorless in the pale gloaming, but not to be mistaken, nor yet to be recognized without a gleam of pleasure. Though Murtagh had no great love for the sea as such, he could not in this alien region fail to find something consolatory in the sight of any accustomed object; and he made for it straightway, down a lane bordered by furrows set thick with their thriving crops. To his mind they

had a vile, outlandish appearance. He felt several degrees less dejected when he presently found himself on the strand, where the crude, harsh smell of the turnips yielded place to those ocean-odors by old acquaintance endeared. It was a rough beach, sloping in ill-defined terraces of shingle, strewn with large stones, on one of which he seated himself, and stared out, across the still, floor-like water. Oftentimes had he sat just so among the wrackwreathed boulders on summer evenings at home; with the difference, it is true, that then he was at home, so thoroughly as to have his house in view very close by if he turned his head. In fact it had been a favorite diversion of his boyhood to watch until the broad disc of the setting sun touched the water's rim, and then scamper up the footslope to reach his door before the scarlet fireball had quite gone under. Generally he had easily won that race. run with his elongated shadow sliding on before him, to shoot up against the white wall, and in the dark room he would always find his mother busy about supper at the hearth, red as if with brands plucked from the fading west. He thought of it now, and added the reflection that here was no sunsetting, but a miserable and undesired dawn. The sun, no doubt. would by and by be swinging up over the dismal fields behind him, and weary hours must pass before he could hope for even the poor comfort of seeing yonder horizon flush with the end of an exile's day.

Thinking thus, he chanced to raise his eyes, and there was a small are of fiery gold low down in the leaden gray haze far out on the utmost verge. As he stared at this half incredulously, it rose and grew, lifting itself up higher, and rounding itself into a full orb, burning raylessly. Beyond question the sun was coming up out of the