R
O N A L D
R o s s
Researches on malaria
Nobel Lecture, December, 12, 1902*
Contents
1. Preliminary
p. 26
2
. The discovery of the parasite of malaria p. 27
3. The problem of the mode of infection
p. 29
4. First researches in India; 1889-1894
p. 30
5. Return to England; 1894
p. 31
6. The theories of King, Laveran, Koch and Manson p. 32
7. Nature of proposed investigations
p. 36
8. Preliminary observations at Secunderabad; 1895
p. 37
9. Secunderabad; 1895. The motile filaments in mosquitos
p. 38
10. Difficulty of the task. The methods devised
p. 39
11. Bangalore; 1895-1897. Progress of work
p. 42
12. The Sigur Ghat; 1897
p. 49
13. Secunderabad; 1897. The fundamental discovery
p. 53
14. Interruption; September 1897-February 1898
p. 62
15. Calcutta; February-April 1898. The theory proved
p. 65
16. The Darjeeling Terai; April-June 1898. Efforts to obtain assistance
p. 72
17. Calcutta; June-August 1898. The route of infection
p. 76
18. Darjeeling District; August-September 1898. Kala-Dukh
p. 82
19. Assam; September-November 1898. Kala-Azar
p. 83
20
. Calcutta; November 1898-February 1899. The work conf
irmed p. 85
21
. England; March-July 1899. Foundation of the Liverpool School
of Tropical Medicine
p. 89
22
. Sierra Leone; August-September 1899. The investigation completed p. 92
23. Confirmation and extensions
p. 94
(1) The work of Koch
p. 94
(2)
The Italian writings p. 96
(3) The Commission of the Royal Society
p. 103
References
p. 105
Plates
p. 110
* The lecture as given on this occasion was only an abstract of the present publication.
26
1 9 0 2 R .R O S S
1
. Preliminary. Malarial Fever, or, as it is often called, Paludism or Intermittent
Fever, is perhaps the most important of all diseases which afflict humanity.
Broadly speaking it is spread over almost the whole of the tropics, and also ex-
tends into many countries which possess temperate climates - being found as
far north as Sweden and Canada. Although, happily, it is not a very fatal dis-
ease, yet it is generally so prevalent in the countries in which it exists that the
sum of the illness which it causes is immense. To take for instance the great
country of India with its enormous population of nearly three hundred mil-
lions, we find from the sanitary returns of the government that the deaths from
fever alone are given at 4,919,591 for the single year 1900; and average roughly
about five million deaths yearly - a population nearly as large as that of Swe-
den and Norway. Although it is not possible to state that all this fever is mala-
rial fever, there are reasons for thinking that most of it must be such. From the
more exact returns of the army and of the jail prisoners in India - returns at-
tested by medical men - we find that in 1900, out of the total of 305,927 per-
sons, no less than 102,640 were admitted into hospital for malarial fever during
the year; and even this large figure is below the truth, because in India many
slight cases of fever are not admitted into hospital at all. The following Table
I
taken from the returns of the British Troops in India for 1900 will enable us to
compare the sickness due to malaria and to other diseases respectively.
It should be noted that the death rate for malaria is here far below the truth;
because, the disease being often very chronic, many of the worst cases are in-
valided to Europe; while in others death is often recorded as being due to inter-
R E S E A R C H E S O N M A L A R I A
27
current affections, such as pneumonia or dysentery, even though malaria may
have been the original or principal cause of the fatal result.
Similar statistics will be found in most of the tropical countries of the world
where statistics are kept at all. Even in such a temperate climate as Italy, the
annual number of cases amounts, according to Celli, to something like two
millions, while the number of deaths may be fifteen thousand a year. For the
great continent of Africa we have, of course, no figures; but we know from
the important discovery of Koch, confirmed by many German and British
workers, that between fifty and a hundred per cent of the negro children al-
ways remain infected from which also we may assume that the terrible in-
fantile mortality among negroes is largely due to this disease.
But malarial fever is important, not only because of the misery which it in-
flicts on mankind, but because of the serious opposition which it has always
given to the march of civilization in the tropics. Unlike many diseases, it is
essentially an endemic, a local, malady; and one which unfortunately haunts
more especially the fertile, well-watered and luxuriant tracts - precisely those
which are of the greatest value to man. There it strikes down, not only the
indigenous barbaric population, but, with still greater certainty, the pioneers
of civilization, the planter, the trader, the missionary, the soldier. It is there-
fore the principal and gigantic ally of barbarism. No wild deserts, no savage
races, no geographical difficulties have proved so inimical to civilization as this
disease. We may almost say that it has withheld an entire continent from hu-
manity - the immense and fertile tracts of Africa; what we call the dark con-
tinent should be called the malarious continent; and for centuries the successive
waves of civilization, which have flooded and fertilized Asia, Europe, and
America, have broken themselves in vain upon its deadly shores.
2. The discovery of the parasite of malaria.
From the first then, the study of this
potent foe of mankind has given a great occupation to science. It is not within
my province at this moment to detail the early steps by which science grad-
ually penetrated the mystery-steps, however, which are not the less interest-
ing to follow. Though it was well known to the ancients, the disease was not
clearly differentiated from other fevers until much later. Towards the middle
of the seventeenth century, however, physicians recognized that in cinchona
bark we possess a drug which is a specific for a certain class of fevers, namely
the intermittent fevers. As Kelsch and Kiener remark, this discovery was not
only an immense therapeutical benefit, but also led to a notable pathological
advance, because it enabled Morton and Torti to prescribe the exact limits of