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The Nobel Prize in Physiology or Medicine 1902
Ronald Ross

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Award Ceremony Speech

Presentation Speech by Professor the Count K.A.H. Mörner, Rector of the Royal Caroline Institute on December 10, 1902

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

Among the stipulations Alfred Nobel set forth in his will, on which the Nobel Foundation is based, that concerning the international character of the prizes occupies an important place. This proves not only his love of mankind and his wish that we should regard one another as brethren, but it is also a witness of his extensive and prescient views more especially concerning medical science and its advancement.

All the branches of medical science and their promotors in different countries have the same ultimate aim, that of gaining the most thorough knowledge possible both about the human body and the processes in it, as also about noxious influences and the means of their prevention. All medical workers unite in pursuing that aim and in doing so feel members of one great fellowship. Nevertheless, the different fields of medical science lie at such a distance one from another, that the individual worker on many occasions must look afar in the attempt to get a thorough view of the progress of the work.

With respect to diseases they are often of different kinds and import in divers regions of the world. For instance, malaria is nowadays of little importance here in Sweden, whereas it is a veritable scourge in other regions. For elucidating this question by an instance from a European country, it may be mentioned that in Italy of late the annual average of deaths by malaria has been about 15,000, and the yearly number of cases is calculated as about two millions. Still more overwhelming are the numbers from India. Of the British Army, amounting to about 178,000 men, close upon 76,000 men were admitted into hospital for malarial fever in the year 1897. In this single year the mortality from «fever» among the civil population in India amounted to a total of more than five millions. It is moreover a well-known fact, that malaria dominates so severely in vast territories that it causes the very greatest difficulties for the cultivation of countries which, but for the malaria, are specially favoured by Nature.

The question of the real nature of malaria, its origin, its manner of entering the organism, and the consequent question of the possibility of preventing this disease, are all of the greatest importance and have from remote ages occupied investigators, for a long time without success.

A very important discovery concerning malaria was made - now long ago, more than two decades - when Laveran, a French army surgeon, ascertained, that malaria is a parasitic disease, caused by a very low form of animal life, that he found in the blood of malarious patients. By this discovery the name of Laveran has for ever become renowned in the history of malaria.

Research about malaria in the last two decades has chiefly been based on Laveran's discovery. Science has thereby been enriched with many an important fact. We have gained knowledge of the different forms of the malarial parasite in blood. We have found, that it differs in the special forms of the disease. We have learned the relations between the parasite and the red blood corpuscles, in which it is chiefly to be found. We have furthermore been able to survey the manner in which it multiplies in the blood; the Italian investigator Golgi has in this respect revealed the remarkable fact that the periodicity of the malarial attacks depends on the appearance of new generations of the parasite in the blood. We have moreover found allied parasites in the blood of several mammals and birds.

The important question, previously mentioned, as to the possibility of the malarial parasite living outside the body, and its way of obtaining entrance into the blood remained unanswered. For some reasons, among others owing to various facts that were known concerning other parasites of an animal nature, it was supposed that the malarial parasite in some way leaves the blood so as to exist in some form in nature, probably as a parasite of some other being. As nothing indicated that the parasite was to be found in the secretions or excretions, the supposition lay near at hand, that suctorial insects would assist in carrying the parasite to a place, where it had to pass the aforementioned part of its life-cycle. Attention was therefore directed to the mosquito, which was thus supposed to spread the malarious infection. The importance of the mosquito in this respect has now been proved. In this case, as in several others, tradition anticipated science; it is even said, that negroes in the East-Africa use the same name for the mosquito and for malaria.

The mosquito theory of malaria was introduced to science by King no less than 18 years ago. The theory, however, remained a conjecture without other evidence than some suggestions given by epidemiological observations. The attempts made in Italy in the early nineties with the view of examining the theory experimentally, and, eventually, proving it to be true, gave results that seemed anything but encouraging; being far more likely to prevent the investigators from following this line.

A person we deem of great merit concerning the solution of the problem is the English investigator, Patrick Manson. It was a change in the appearance of the parasite, which was sometimes observed to occur, as the blood is shed, that Manson especially regarded as the first stage of its life outside the body. This phenomenon has afterwards been shown by the American pathologist Mac Callum to imply an act of reproduction of the parasite. Manson was moreover guided by his experience regarding another parasite of the blood, a little worm, filaria, the transference of which from one part of its life-cycle to another he had found effected by the mosquito, and more particularly by special species of the mosquito. By his views set forth on malaria, and by exciting expectation that the solution of the malaria problem was to be found in the direction he indicated, Manson gave an impulse to the further testing of the mosquito-theory and at last to its being established. Manson, who lived in England, had no opportunity of taking up the experimental work of the problem. The solution came from India.

It was an English army surgeon in India, Ronald Ross, who, impressed by Manson's induction, undertook the experimental testing of the matter. Critically arranging his experiments, he caused mosquitoes that were hatched from larvae in the laboratory, to bite malarious patients, and endeavoured to follow the parasite in the body of the mosquitoes. The results of the first two years' labour, although assiduous and scrupulous, gave little promise of success. But in August 1897 all at once he made vast progress towards his aim. While experimenting with another, less common species of mosquito, in the wall of its stomach he found bodies that very probably were an evolutionary stage of the human malarial parasite.

Ross, being prevented by circumstances from pursuing his plan in studying the malarial parasite of man, continued his work with an allied malarial parasite of birds. The result was that not only could he confirm his discovery concerning human malaria, as he found corresponding facts for avian malaria, but he also in a short time succeeded in revealing the further development of the avian malarial parasite in the body of the mosquito.

This development is briefly as follows. In the stomach of the mosquito a process of fecundation at first takes place; the form of the parasite, thereby produced, penetrates the stomach wall, embedded in which it grows to button-like structures projecting into the body-cavity. In these structures a large number of elongated organisms, «sporozoites», are formed. On the consequent bursting of the said structures the «sporozoites» escape into the general body-cavity of the mosquito, and accumulate in the salivary or poison glands, which are in connection with the proboscis with which the bites of the insect are inflicted. A bite of the mosquito, at that time, inoculates the parasite, and if the individual is susceptible to the parasite, this develops in the manner known and described long ago.

Ross's discoveries into malaria were immediately followed by a series of important works.

Thus the Italian investigator, Grassi, in association with his colleagues, Bignami and Bastianelli, proved that the human malarial parasite not only in its early stage, already detected by Ross, but also in its further development undergoes the same evolution that Ross described for the growth of the avian malarial parasite in the body of the mosquito. Grassi also has precisely indicated the species of mosquito that are of import for the malaria of man. Many valuable works, besides these, have been issued by Ross, by the Italian investigators, by Robert Koch and by many others, works, by which not only our knowledge of the malarial parasite has been enlarged, but this knowledge has been made useful in combating and preventing malarial disease.

The eminent scientific value of Ross's work, its importance as a basis for the success of the recent investigations into malaria, its rich contents as regards the art of medical practice and especially hygiene, will be obvious from the above.

It is owing to these merits, that the Professorial Staff of the Royal Caroline Institute has decided to allot the Medical Nobel Prize of this year to Ronald Ross.

 

Professor Ronald Ross. In announcing that the Professorial Staff of the Royal Caroline Institute has decided to award to you the Medical Nobel Prize of this year on account of your work on malaria, in the name of the said Institute I congratulate you on your investigations. By your discoveries you have revealed the mysteries of malaria. You have enriched science with facts of great biological interest and of the very greatest medical importance. You have founded the work of preventing malaria, this veritable scourge of many countries.

From Nobel Lectures, Physiology or Medicine 1901-1921, Elsevier Publishing Company, Amsterdam, 1967

 

Copyright © The Nobel Foundation 1902
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