Robert Dyer Lyons

Robert Dyer Lyons was a native of Cork and a professor of medicine and pathology at the Medical School of the Catholic University of Dublin. In 1857 he visited Lisbon to investigate a yellow fever outbreak. 

Lyons, the son of a well-to-do merchant, was 31 when he headed to Lisbon. He was already an accepted authority on the use of the microscope and, at the invitation of the British Government, had spent a year as Pathologist-in-Chief in the Crimea investigating the fevers that were depleting the British forces. He had requested leave of absence from the rector of the Catholic University on 22 November 1857, explaining that 'the most recent accounts of the great epidemic now raging at Lisbon concur in describing it as yellow fever of a very bad type. I am extremely desirous of availing myself of this opportunity for investigating the pathology of this very formidable disease.'

There had been a yellow fever epidemic in Lisbon in 1723. A few isolated cases occurred in Porto in 1850 and 1851 and there was a small epidemic in 1856. The few cases that occurred in Lisbon early in August 1857 attracted little attention but, by September, there was an epidemic. Many people left Lisbon and others would have joined them were it not for the example of Dom Pedro V who stayed there and visited the sick. Most people stayed indoors as much as they could and a quarantine was eventually introduced.

The rector agreed on 23 November that Lyons should go and contributed £50 towards his expenses. By the time he reached Lisbon, the epidemic had passed its peak but he was welcomed by the civil governor, the Count of Sobral, and by the medical faculty at the university who gave him permission to carry out post-mortems, of which he did 24, noting that the skin was invariably yellow. "The tint varied a good deal; it was sometimes a light, faint, sometimes a rich canary or gamboge colour, sometimes a light, faint, sometimes of a deeper yellow with a more-dusky hue ..." He was received by the king.

Strangely, although perhaps pleasingly to our male Portuguese members, he commented on the size of the penis of the male corpses, noting that 'I am informed (on medical authority) that a very enlarged state of the genitals is by no means an uncommon physiological condition amongst the population in question.'

At this time the method of transmission of yellow fever was unknown and Lyons set about investigating possible causes, for example by making a study of the climate, noting in particular the rainfall patterns of the previous years. He commented on the poor water supply, the lack of drains and the disposal of excreta by throwing it into the street, which at least gave him the opportunity to carry out scatological studies.  He pointed out that the sewers were often blocked when they reached the Tagus and that there were malicious odours coming from the river.

While the prevailing view was that the yellow fever had arrived on a ship from Brazil, Lyons found no evidence that it had been imported, reporting that just as many cases were found in the higher parts of the city as close to the port. The studies he conducted made him believe that yellow fever was not the result of human-to-human transmission (we know now that it is transmitted by mosquitos), pointing out that while many people had fled to Sintra there were no reported cases there. He noted that while some doctors had died from the disease there was little reluctance to attend the ill. In fact, he complimented the people of Lisbon for the attention that they paid to the sick. 

Lyons published a detailed report in a medical journal and included an account of the disease in his Treatise on Fever. Dom Pedro V awarded him the cross and insignia of the Ancient Order of Christ. His report was printed by HMSO and submitted to both houses of the British parliament. He was elected to parliament in 1880 and died suddenly in 1886.

Main source: Lyons, J. B. ‘Dublin Observer of the Lisbon Yellow Fever Epidemic’.