Winnifred Mary Ward
|HARRY MARSHALL WARD. — The heaviest loss which botanical science has experienced during the past year that of Professor Marshall Ward of Cambridge. He was one of our six honorary British Fellows, and if I left notice of him to the last it is because what he has done has so informed our generation, and has so pointed the way for the future in the lines of botany in which he was expert, that I wish to use the occasion of this address for a survey of some of the work he accomplished. In these days of rapid absorption of new facts and ideas into general stock of knowledge to serve as starting points for new discoveries of facts and further suggestions, the exact service of individuals is apt to be forgotten or overlooked and therefore, although the retrospect of another generation will assuredly differ somewhat from the view we are able to take of the work of contemporaries, it is well that we put record our opinion, especially in the case of those whom we regard as brilliant. Into this category Marshall Ward comes. There has been in our time no more effective teacher, using the term in its widest acceptation. The present general knowledge of, the present recognition of, the importance of plant pathology and of disease caused by and affecting plant life in relation to great industries in this country, is in great measure an outcome of his teaching, whilst the attitude of science to the problem of biology involved in the relationship of organism to organism has solid support in the results of his researches. In order to bring within near focus the course of his life, I give here a chronological table and also a list of his publications. In the preparation of these I have been greatly assisted by Mrs. Marshall Ward.|
Biography.Born at Hereford in 1854, the eldest son of Francis Marshall Ward, Harry Marshall Ward was educated at Lincoln Cathedral School and a private school at Nottingham. Inheriting considerable musical talent, the intention was that music should be his vocation. His real bent was otherwise. Natural science claimed him, and he went in 1874 to London as a prospective school teacher of science to the classes at South Kensington, then only recently established under Huxley as an outcome of the rebirth of Biology that followed upon the appearance of Darwin’s Origin of Species. There is an element of romance in the circumstances that finally secured Ward for the career in which he acquired distinction. The fellow student who sat beside him in Huxley’s laboratory was a Mr. L. A. Lucas. He was struck by the quality of the work Ward did, and urged him to go to Cambridge, then also awakening under the stimulus of freer conception of living things. The res angusta domni barred the way, however, ambitious though Ward was to follow out the suggestion.
Mr. Lucas, being a man of private fortune, provided anonymously the necessary funds, and thus it came about that Ward vent to Cambridge, became a scholar of Christ’s College, took his degree from there in 1879, obtaining First Class Honours in Botany in the Natural Science Tripos. It was a life regret to Ward that his benefactor died early in the East, and before he could know the benefit to science that his benefaction had brought.
During this period of education Ward worked for a time in the laboratories of Sachs at Wűrzburg and of De Bary at Strassburg, and he also had preliminary training as a teacher by co-operating in the science classes at south Kensington (1876), and at the Owens College, (1877), and by lecturing at Newnham College Cambridge. (1879).
After graduation he spent two years in Ceylon as cryptogamist to the Ceylon Government, and on his return Berkeley Fellow of Owens College (1882), and subsequently assistant lecturer and demonstrator in Botany there (1883) Meanwhile his old college at Cambridge elected him to a Fellowship (1883). In the same year he married the eldest daughter of Francis Kingdon, Esq., of Exeter. Two daughters survive.
The year 1884 nearly brought Marshall Ward to Scotland as Professor in Glasgow. That he did not come was a disappointment to him. I may take this opportunity to tell the story of how this came about, and to remove misapprehension that has gathered round the circumstances. My election from the Regius Chair of Botany in Glasgow to the Sherardian Chair in the University of Oxford at the beginning of March 1884 left but a short period for the election of my successor by the Crown before the opening of the summer session. The experience of the University of Glasgow in a preceding vacancy did not encourage it to risk an appointment delayed beyond the beginning of the session, and I was therefore invited by the University to carry on the work of professor of Botany during the following summer session. As my Oxford work did not begin until October and the Vice-Chancellor acquiesced, I accepted the invitation. The University resolved not to accept my resignation and not to intimate a vacancy to the Government until the close of the summer session. This information was conveyed to several aspirants to the Chair amongst them to Marshall Ward. The session was about three weeks gone when my colleague in the Chair of Anatomy (Professor Cleland) received a letter from Professor W. R. M’Nab of Dublin to the effect that he had been appointed by Sir William Harcourt, then Home Secretary (in whose hands such appointments then were), to the Chair of Botany at Glasgow, and asking information as to my movements. How this appointment came to be made I do not know. The University of Glasgow would not accept it, holding, as was true, that no vacancy had been announced by it to the Crown, and that the selection had not been made from an adequate field of candidates, and in particular mentioned Marshall Ward’s name; at the same time I was asked to defer my resignation until the University desired me to send it in; this did not happen until near the close of the year, and then both M’Nab and Marshall Ward were passed over.
At Manchester, Ward remained until 1885 when he took up the appointment of Professor of Botany at Cooper’s Hill College, a college which this year (1906) has ceased to exist. There he remained for ten years, until, on the death of Babington, he was called in 1895 as Professor of Botany to the University of Cambridge. For some years he had been suffering from an ailment that wrought sore havoc upon his frame, and his death in August last, at the early age of fifty-three, came as no surprise to those who had seen him recently.
By his death a warm friend and keen man of science has gone from us, to whose admirable personal qualities many tributes have been paid by pens of those who knew him well. Here I will only say that my sense of individual loss is deep, for our friendship began in 1880, as we voyaged to the East, and was strengthened by intimate association in many things during after years.
As a teacher in the institutions to which he was attached, the dominant characteristic of Marshall Ward was his boundless enthusiasm, which overflowed to his pupils. The gift of ready and lucid exposition was his, and he thought clearly. His facile draughtsmanship, giving life to his delineations, added to his power.
Full of knowledge of his subject and its bearings, he at times overwhelmed his hearers with apt reference and technical illustration. Always interesting in the lecture hall, in the laboratory his dexterity and industry were a stimulating example to the beginner, to whom he rightly gave much personal attention, and his direct help and suggestive outlook encouraged the advanced pupil.
But Ward’s teaching was not only thus confined. He appealed to a wide audience besides his academic one. Practical problems associated with the activities of plants whether useful or hurtful, always attracted him and he ‘readily responded to the many claims made upon him to discourse on the scientific principles underlying practice in large industries which were based upon plant life. Thus brewing was a subject to which he gave much attention investigating the fungi of vats and crystallising the points of his teaching in contributions to the periodicals of the industry.
The question of timber and its diseases came prominently under his notice as an instructor at Cooper’s Hill of young men about to enter the Indian Forest Service, and his books on the subject, as well as upon plant-disease as a whole, have done much to spread sound knowledge.
No botanist of our time has done so much to promulgate correct views upon the work of plants as factors in our everyday life. The economic side of plant life fascinated him indeed, and in his address to the British Association at Toronto he took this as his subject. Marshall Ward was a great teacher. But the greatness of a teacher lives, however, only by tradition, and weakens as those who have been directly influenced by it appear. A new generation has its own teachers with the basis of comparison with the old. Marshall Ward has, however, written his name large on the roll of fame to all time through the brilliant contributions to natural knowledge he has made, by his illuminating treatment of biological problems, and by the new lines of research he has initiated. No one of our generation has done more solid work for botanical science. The twenty-seven years of his “active work” of investigation were full years. The records of his work are laden with achievements and fertile suggestion.
At the outset of his career, and under the influence of the researches, which Strasburger in particular was giving to the world, Marshall Ward took up the question of embryo -sac development in Angiosperms, and in the two papers, which he published, he established many new basal facts, now the common property of botanists. Later, in 1887, in a paper upon the fruit and seeds of Rhmtnus, he, along with his pupils, published the results of an investigation, which was of the greatest interest, for he showed that in the raphe of the seeds there is localised a ferment which, when in water it comes in contact with the glucoside xanthorhamnin located in the pericarp, breaks it up into glucose and the crystalline yellow rhamnin which is the matter of the yellow dye of the Persian berries, as the fruits of Rhamnus are called. By this discovery he gave the scientific explanation of empirical points that troubled dyers. Why, for instance, the crushed fruits yield a satisfactory colouring matter, whilst the pericarps alone do not. Further, he advanced reasons for thinking that the glucoside is a storage material for the young plant, quoting as analogous cases the well-known ones of the amygdalin glucoside and emulsin present in separate cells of the seed of bitter almond, and the myrosin ferment and myronate of potassium in mustard. I mention these researches first because they are the only cases of elaborate investigation published by Marshall Ward outside the group of the Fungi, Mycetozoa, and Bacteria. They show, however, that in any field he entered upon he would have obtained brilliant results.
The critical moment that determined the chief field of Marshall Ward’s research was that when in 1879 he was appointed to investigate in Ceylon the coffee-leaf disease. From that moment Fungi in the widest sense and their work were the subject of his assiduous research. On him in fact descended the mantle of Berkeley, our great Cryptogamic botanist of the nineteenth century. During the past couple of decades Marshall Ward has been our recognised authority upon the group and its activities, and he has given us story after story of the life and inter-relations of different forms sketched with the accuracy of observation and judgment of circumstance that became one who had been in touch with De Bary and through him had acquired the tradition of the school of the Tulasnes. Dominating all his brilliant inquiries is the endeavour to solve the questions involved in parasitism ―the influence exercised by the host on the parasite, and conversely of the parasite on the host and the mechanism of the attack—in fact, the fundamental problem of the interaction of living organisms. His first study in this group was that of Hemileia vastatrix, the fungus of the coffee-leaf disease. It will be within knowledge of many of you that in the seventies the plants on the coffee estates in Ceylon were attacked by an epidemic, which brought ruin to the cultivation, and in response to the appeal of the planters the Colonial Government appointed Ward to investigate it. There is always a wide gap between determination of a cause in such a case and the devising of an effective remedy. The first of these Marshall Ward succeeded in doing with absolute clearness. As regards the second, the planters ultimately adopted the radical cure of abolishing the cultivation of coffee and betaking themselves to other crops. That the industry should thus disappear was no reflection on Ward’s work. The fungus itself was shown by Ward to be a Uredine, and in working out its history many problems of infection and development presented themselves, and became, if not solved at the time, objects of attack in the future. Whether or not from this early association with a Uredine, the group became a favourite one with Marshall Ward. As you know, it is classic group, inasmuch as it was in it that De Bary first traced the wonderful history of a metoxenous pleomorphous parasite and established the condition know as Heterœcism. The very last research in which Marshall Ward was engaged was concerned with the elucidation of problems in the group first suggested by his studies in Ceylon. It would be impossible for me in the time at my disposal to deal as I would wish with all the discoveries of Wand in the domain of the Fungi. I propose to select for mention to you some, through which a clearly marked step forward was the outcome of the research. As then I was talking of the Uredines. I may first of all refer to this group, though his most suggestive work on it was the last Ward did. Specialised parasitism is one of the most interesting facts that have become known in connection with - their life histories. We now know that, for example, the classical Puccinia graminis is really an aggregate of morphologically different forms, but over and above this there are also physiologically different forms, i.e. forms which, though indistinguishable outwardly and structurally, yet are sharply distinct in their parasitism. Thus the .Puccinia graminis of wheat does not attack rye, barley, and others of the grasses This is what is meant by specialised parasitism, the forms being variously called adapted species, or races, biological species, and so on. What is the cause of this? The problem here is the old one of immunity and susceptibility. And to the solution of this Ward set himself vigorously.
The suggestion that anatomical considerations, presence of hairs, wax, etc., were important factors, was advanced frequently and received some support, but Ward was able to show conclusively that these have nothing to do with it. He forces us to recognise that there are two stages, one of application or inoculation by the spore, which germinates and. sends a tube into the air chamber of the stoma, but that is not necessarily followed by the infection, which means the entry of the germ tube through the cell wall bounding the air chamber. And ultimately he was able to prove that the infection depends upon the reciprocal presence of enzymes and toxins and antitoxins in parasite and host. Nor was this all. Marshall Ward was able to establish his theory of inuration and bridging species. That is to say, he found it possible to educate a parasite, which was harmless to a particular host species, to attack it successfully through cultivation successively upon allied forms. Thus, given a parasite growing upon a grass A, but to which grass E is immune, it is possible by growing the parasite successively upon certain forms B, C, D, to educate it so that it will attack E. These intermediate forms Ward termed bridging species.
All this work on the Uredines brought Ward into conflict with the well-known Swedish agricultural professor Eriksson, who had given much attention to the study of the epidemics of rust that occur in Sweden. The point of conflict concerned the method of perennation of the metoxenous Uredines. When it was discovered that plants like the barberry, Rharnnus, Anchusa, were hosts of stages in the pleomorphous life history, the prophylaxis that naturally suggested itself was destruction of these in the vicinity of cereal crops. That has been a matter of policy in many areas. But now, despite this abolition of the host of an essential winter stage of the parasite, it is found that the epidemic of rust is as virulent as ever. How is this to be explained? All observers, from De Bary and Ward, have sought in vain for a perennating mycelium, and it has been shown by Ward and others that uredospores may perennate and germinate in the next season, and thus a satisfactory explanation would be forthcoming of the occurrence of the epidemic. Eriksson, however, will have none of this but he introduces what he calls “the intracellular mycoplasm life of the fungus,” what he calls for shortness his mycoplasm theory according to which, by some mysterious method, the plasm of the fungus becomes combined in a long latent symbiotic life with the protoplasm of the host, forming a mycoplasm, and only shortly before the eruption of the rust pustules does it enter into a visible state assuming the form of a mycelium. Of this hypothesis Marshall Ward after the fullest examination and discussion, was merciless in his condemnation. Savouring as it did of the fanciful, not susceptible of any optical demonstration, he would have none of it, and his last appearance at a meeting of botanists was at the British Association at Cambridge last year, when the question was fully discussed, and not to the advantage of Eriksson.
On the recrudescence of the question of the nitrogen supply of green plants in 1886, brought about by the work of Frank on the mycodomatia of Legumiuosæ and the mycorrhiza of forest trees, Ward entered the field, and by his discovery of the method of infection of the root hair and the subsequent stimulus of the root to the development of the mycodomatia practically settled the question. Ward thought that the organism entering the root hair was a mycelial fungus. At that time the curious coenobial forms of bacteria had not been investigated. Now we know that Ward’s infection thread is really a bacterial colony. This does not detract from the merit of Ward’s discovery, which, as I have said, was crucial.
Another critical piece of work was that in 1888 upon a disease of the lily, for in course of this he was able to show the exact method by which a fungus mycelium pierces the cell wall of its host, and to isolate the ferment by which the penetration is effected.
In the middle eighties the organism known as the ginger beer plant came into special notice. Many botanists received specimens with requests for information regarding it. As you know, the plant consists of lumps of gelatinous substance, which has been long in use in country districts for the manufacture of home-made ginger beer. When the gelatinous lumps are placed in a saccharine solution with some bits of ginger in a bottle, a fermentation is set up which results in the liquor so commonly used. Mythical histories attached to the origin of the gelatinous mass―brought from the Crimea, Italy, and so on—and the plant handed on from family to family. In 1887 the plant came to Professor Marshall Ward, and he began an investigation—one which ultimately extended over several years. The outcome of it was that the ginger beer plant was shown to be composed of two essential ingredient, plants, with several others present as accessory non-essential forms. Of the essential, one is a bacterium, B. verniforme, a distinct species, the gelatinous sheaths of which make up the jelly of the ginger beer plant. The other is a yeast, Sacharomyces pyriforme, also a distinct species, to which the alcoholic fermentation is due. Not only was this determined by analysis, but also by synthesis. Further, the research led to the development of a new conception in that of symbiotic fermentation, i.e. the bacterium is favoured by obtaining some substance or substances directly they leave the sphere of metabolic activity of the yeast cells. The yeast, on the other hand, benefits by these substances being removed and destroyed, and amongst these the C02, which seems to be essential for the bacterium. (A comparison with the symbiosis of a gelatinous lichen naturally suggests itself.) This idea of symbiotic as compared with metabiotic, where one organism prepares only the ground for another, and antibiotic, where one organism ousts the other by poisoning the medium, is a fertile one.
I now come to speak of an investigation the labour of which would have daunted most men. I refer to that of the bacteriology of Thames water. This he undertook for the Royal Society in 1892, in conjunction with Professor Percy Frankland. The actual bacteriological part of the work was taken up by Marshall Ward himself. For work of this kind he was well prepared, having already published his views upon the characters employed in the classification of Schizomycetes. It is difficult for an outsider to realise the industry, the constant attention, required for this bacteriological work. It involved the isolation and growing through all their life stages in pure culture of the many forms met with in the water and then the determination of their several capacities whether these made for health or disease in the user of the water containing them. But it was the kind of work in which Marshall Ward reveled. Such of the results as are published in the Reports of the Royal Society are compendious and thorough With his characteristic intuition, Marshall did not fail to follow up clues that might lead to framing a general conclusion, and one of the most valuable products of this bacteriological work was his demonstration that light arrests development of the bacteria and ultimately kills them. This was no more than might be expected, and had indeed been vaguely forestated. But Marshall Ward went further, and by an elaborate series of experiments proved beyond question that the bactericidal action lay in the blue region of the spectrum. As a side issue the question of colour in bacteria in its relation to the action of light was a subject investigation, and its parasolar value was demonstrated. The line of work initiated by this discovery Marshall Ward had proposed to follow up through other processes of the vegetable kingdom, but had not accomplished this at time of his death.
The references that have been made will suffice to indicate the extent and far-reaching character of Marshall Ward’s work in Mycology, and one cannot but feel assured they establish his claim to be reckoned one of the great investigators of our time, who has not only added to sum of knowledge, but opened up new avenues to further victories over the unknown.