To mark the digitisation of medical archives in the India Office Records, I am highlighting some seminal research relating to Ronald Ross, who lived from 1857 to 1932, and his important work discovering the causes of the transmission of malaria.

By the late 1870s, a miasmic theory – or ‘bad air’ theory – of transmitting malaria was falling from favour and being replaced by a focus on biological transmission. Corrado Tommasi-Crudeli and Theodor Klebs had isolated a bacteria from water which they claimed acted like malaria. A French physician, Charles Louis Alphonse Laveran, had shown that malaria was spread by parasites by performing necropsies on malaria victims. Following this groundwork, a combination of work from Patrick Manson, Giovanni Grassi and Ronald Ross added ultimately conclusive developments to the theory.

Sir Ronald Ross was born in Almora in Uttarakhand in 1857 to Sir Campbell Ross, a general in the Indian Army, and his wife Matilda. He entered the Indian Medical Service in 1881. During a year’s leave, he studied for the diploma in public health from The Royal Colleges of Physicians and Surgeons in England taking a course in bacteriology.

Image from Wallis Mackay’s The Prisoner of Chiloane. Credit: British Library/Flickr (CCO Public Domain)

Ross’s interest in malaria began in 1892 when he was converted to the idea that the malaria parasites were in the bloodstream. Patrick Manson demonstrated this to Ross in 1894. In India, Ross was investigating if mosquitoes were connected to the transmission of malaria, but he was called away from malaria-infested areas on Indian Medical Service duty.

This frustrated Ross. He sent a letter requesting to be “put on special duty for a few months after relief at Bangalore to enable him to investigate the truth of Dr Patrick Manson’s theory of the Transmission of the infection of malaria by means of the mosquito”.

The work would be carried out by someone who was “a microscopist and bacteriologist with a bent towards original research”. Ross planned to follow Manson in proving that it was the mosquito which spread the disease. He wrote instructions on how to carry out the experiments and listed three necessary proofs:

• That the parasite went through the same change inside the mosquito as it did in blood drawn from humans

• That the parasite was capable of developing and living inside the mosquito

• That the parasite could be communicated from the mosquito to humans.

On August 20, 1897, in Secunderabad, Ross made his breakthrough discovery. While dissecting the stomach tissue of an Anopheles mosquito, fed four days previously on a malarious patient, he found the malaria parasite. He noted these memorable words in a poem:

“..With tears and toiling breath,
I find thy cunning seeds,
O million-murdering Death”

Ross continued his research in India and demonstrated that mosquitoes could serve as intermediate hosts for bird malaria. He showed that the route of infection was through the bite of a mosquito with experiments on four sparrows and a weaver bird. The account of these findings was presented to the British Medical Association in July 1898. In 1902 Ross became the first Briton to be awarded the Nobel Prize for Medicine.

This article first appeared on British Library’s Untold Lives blog.