Ronald Ross Nobel Lecture

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soma, 

and also feeling that it was quite beyond the power of one man to com-

plete as quickly as the interests of humanity demanded the work which re-

mained to be done, I now made strong efforts to obtain assistance. The help of

a single medical man to collect mosquitoes and cases of malaria for me would

certainly have enabled me to reach the last proofs in a month or two; and be it

remembered, the mortality from fever in India alone is said to amount to

something like ten thousand persons every day. When, however, I asked the

Director General for the services of one or more junior medical officers, I was

told that none could be spared at the time. As a matter of fact there are always

many medical officers in military employment in India, who can be spared if

they are urgently called for; and the truth is that the necessary trouble was not

taken. I then wrote to Manson begging him by all means in his power to ob-

tain assistance for me from England; and thought that the Royal Society,

which is subsided to a small amount by Government, might afford to give it.

The matter was considered; and it was finally agreed to appoint, with the help

of the Colonial Office, a commission of three gentlemen to investigate mala-

ria. Two of these were sent in the autumn to study the subject - in Italy; and,

after much difficulty, the third was allowed to come to me. He arrived at

Christmas with orders to stay for two months - not to help me but to verify

my statements!

That was all the help I received. The excuse is that my work had not been

confirmed. But it had been accepted by Laveran, Manson, Metchnikoff, and

Nuttall, who at least knew the subject. Was not this enough to justify the ex-

penditure of a few hundred pounds in so great a cause? I mention these facts

because it was largely this failure to obtain assistance which drove me from

India some months later; which delayed the completion of my work for more

than a year, and which postponed the adoption of an energetic prophylaxis in

India until the present. Not mine the fault: the truth is that for some inexpli-

cable reason men will never recognize the transcendent importance of investi-

gation into the causes of those great diseases which destroy them.

The rest of my time in this district was spent in making attempts to find a

suitable place in the intensely malarious areas at the foot of the mountains for

researches on human malaria. This alone was a matter of no little difficulty, as

the locality was new to me and I could obtain no accurate information regard-

ing the disease. I worked especially at a place called Punkabari, situated a few

hundred feet above the plain. A hospital and plantation existed here, and there

was a large village some miles away on the plain. But the results were not grati-

fying; few dappled-winged mosquitoes could be found, as the rainy season

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had not yet commenced; while to my grief I discovered that the plague-scare

was, if anything, stronger here than in Calcutta. So terrified were the natives,

that on one occasion, when one of my men shot a sparrow for me in the vil-

lage, all the coolies in the neighbourhood ran away for miles into the jungles,

costing the planters much money and trouble before they could be induced to

return. In fact I was given to understand that scientific investigations were not

required there at the moment! Indeed it soon became apparent that I was only

wasting much valuable time; and I consequently determined to complete my

researches on Proteosoma at Calcutta without further delay.

17. Calcutta (June-August, 1898). The route of infection. 

On my return to Cal-

cutta (4th June) I found it still quite impossible to obtain cases of human mala-

ria for my work, and therefore proceeded at once with the life-history of Pro-

teosoma. 

The most wonderful of all the phases of this history was now to be

revealed. I had traced the development of the pigmented cells up to their ma-

turity and subsequent rupture and discharge of their contents into the body-

cavity of the grey mosquitoes. I could not see at the moment what happened

to these contents; yet upon this point depended the vastly important ques-

tion of the route of infection in malaria. But, when I had broken off my work

a few weeks previously, the contents had appeared to consist of little more than

a pure fluid.

Hitherto my mosquitoes had been dissected in water or a weak solution of

salt, and I had had no time for methodical staining. A strong salt solution was

now used and the secret was revealed. The contents of the mature pigmented

cells did not consist of clear fluid, but of a multitude of delicate thread-like

bodies, which, on the rupture of the parent cell, were poured into the body-

cavity of the insect, and which were evidently spores.

Fig. 4. Sketch of thread-like bodies (sporozoids or blasts) escaping from mature rup-

tured pigmented cell (zygote). From letter of Ross to Laveran, dated 18th July, 1898.

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77

What happened now to these spores in view of the theories mentioned in

section 12? Did they escape into the water according to Manson’s ideas; or

were they voided by the intestine according to mine; or did they in some

mysterious manner work their way into healthy persons during puncture,

according to the theories of King and Bignami and later of myself? But the

staff of theory was no longer necessary; plain research would suffice.

Here there was another sharp but short struggle. I saw that the thread-like

bodies, although apparently without motion themselves, were soon scattered

by the insect’s circulation all through its body; but beyond this I could not

follow them for some time, in spite of the most assiduous endeavours. They

seemed to have been created without object.

On the 2nd July however, I found in the thorax of a mosquito a large cell

which, surprising to state, contained within it several of the thread-like bodies.

They were able then to work their way into cells; but what was the cell? On

the 4th July, while working upon another mosquito, I found that the thread-

like bodies seemed to become more and more numerous towards a point in

the thorax - as if they were converging toward some destination. At that point

there were numerous cells such as I had seen on the 2nd July. They were at-

tached to a duct and were all contained within the same capsule - they con-

stituted in fact some kind of gland. In all these cells there were hundreds of the

thread-like bodies, floating loosely at all angles to each other like fish in globes

of glass. Close by was another lobe of the gland similarly full of the spores.

I was at the summit but not on it. I did not know what the gland was. I knew

the appearance of the cells it is true, but in spite of my thousand and more dis-

sections I had by no means acquired a full knowledge of the macroscopical

anatomy. I found it by no means easy to meet with the gland again. On the

8th July the mystery was solved. The gland lay in the neck and upper thorax-

Fig. 5. Thread-like bodies (sporozoids) in cells of salivary gland of mosquito. From  letter

of Ross to Laveran, dated 18th July, 1898.

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