From an Easy Chair

by Sir E. Ray Lankester

At Ismailia, on the Suez Canal, malaria was almost universal; in 1866 there were in a population of eight thousand, 2,300 cases. In 1897 there were over 2,000, and in 1902, when Ross was asked by the Prince d’Arenberg to visit the place and advise as to measures to be taken, there were 1,551 cases. Ross directed the filling up of the breeding pools. The marshes were filled up with sand, the irrigation channels were deepened or treated with kerosene oil (which spreads as a fine film, and chokes the gnat larvæ), and the cess-pits were rendered uninhabitable by chemical treatment. In one year the cases of malaria fell to 214, in 1905 they were only thirty-seven, and now the Suez Canal Company officially reports, “all trace of malaria has disappeared from Ismailia.” The same satisfactory results have been obtained in Port Said, in Khartoum, in Port Swettenham of the Federated Malay States, in Havannah City, in Panama, and, in fact, wherever intelligent conviction has led to the active and complete employment of the methods necessary for the destruction of the gnats. Under the British Government of India and the African and West India Colonies, little has been done. Why? Because of the handmaiden theory and the ostrich-like refusal of our officials to face and accept the master.

An even more wonderful and beneficent result has been obtained in the case of that terrible disease “Yellow Jack,” or “Black Vomit”—the yellow fever. Owing to the discoveries and definite proof by Ross as to the part played by gnats in malaria, the able medical men in the public service of the United States of America have thoroughly examined experimentally the mode of infection of human beings with the germ of yellow fever, and have conclusively proved that infection is solely and entirely due to the bite of one species of gnat—the Stegomyia fasciata. They have proved to absolute certainty that yellow fever is not carried through the air, nor by food or drink, nor by contact with infected persons or their cloths or emanations, but only by the fasciate gnat, a house-frequenting species, which sucks the blood of a yellow fever patient, and after twelve days, and not till then, becomes capable of imparting the infection to those whom it may stab or “bite.” The firm demonstration of this fact was not made without great devotion, courage, and self-sacrifice. In the ardour of their pursuit not a few of the experimenters risked and lost their lives. Among these the name of Dr. Lazear, of the United States Army, is prominent. He deliberately permitted himself to be bitten by a stray mosquito in a yellow fever hospital, in order to show that the insect could convey the infection. He was bitten on Sept. 13, 1900, and died on Sept. 25, having proved his point.

The actual germ, microbe, or minute parasitic organism which causes yellow fever, and is carried by the fasciate gnat, has not yet been detected. Nevertheless, without seeing and isolating the microbe, the medical men of America (Sternberg, Finlay, Carroll, and others) have, by destroying the gnat and preventing its access to men—especially to patients already infected, and, therefore, certain to infect the gnats and cause them to spread the disease—practically made an end of yellow fever in many great cities of the New World, where it was only six years ago an ever-present horror, striking men down with a suddenness and with a deadliness which paralysed human activity. Here, as in other cases, intelligent appreciation of the results of science by a governor or a municipality has saved thousands of lives. On the other hand, in Rio de Janeiro, “the opposition encountered by the sanitary authorities of the city from political factions and the ridicule to which they were subjected by the local Press” were insuperable (I quote from an official report), and so a few more thousand lives were sacrificed before the master was recognised and the proffered safety accepted. In Vera Cruz, in New Orleans, and in Panama yellow fever has been reduced to a vanishing quantity by removing the pools and tanks in which the fasciate gnat can breed, and by making use of wire-gauze to prevent the access of mosquitoes to houses, bed-chambers, drains, and baths, and especially to prevent not only their access to, but their egress from, the rooms and beds of patients already infected with disease.

In the city of Havannah, during the American occupation of Cuba (1900-1903), Colonel Gorgas reduced the death-rate due to yellow fever from an annual average of 751 to so small a figure as six. The same energetic and faithful administrator has been at work, with even more remarkable results, in the canal zone of the Isthmus of Panama since 1904. The attempt of the French to cut the canal was foiled chiefly by yellow fever and malaria. It is estimated that their effort cost quite 50,000 lives. Assisted by an able and enthusiastic staff, and charged with the task by a Government which comprehends the fact that the really “practical men” are the men who recognise science as the master (not as the negligible eccentric handmaid), Colonel Gorgas has banished the mosquito from his zone of occupation. As a consequence there is neither malaria nor yellow fever on the Panama works. In 1906 the total death-rate amongst 5,000 white employés on the Panama Canal works was only seven in the thousand. Further, in last April the daily sick-rate of the total force of about 40,000 people was only seventeen in the thousand. Colonel Gorgas declares that there is but little sickness of any kind among the Americans in the employ of the Panama Commission, and that they and their wives and children are fully as vigorous and robust in appearance and in fact, as the same number of people in the United States. There is no reason why the centres of wealth, civilisation, and population should not again be in the tropics, as they were in the dawn of man’s history.

12. Malta Fever

Mediterranean or Malta fever was for long confused with typhoid and other fevers. Our soldiers and sailors at Malta, Gibraltar, and Cyprus, as well as many frequenters of the African and Asiatic shore, were subject to this disease, and often incapacitated by it. In 1887 Colonel David Bruce discovered in the blood of patients the minute Micrococcus melitensis, which is its cause, and established the fact that it is a definite independent disease. The hospital at Malta has received as many as 624 patients in a year suffering from Malta fever from among the 8,000 soldiers on the island and the 12,000 sailors on the Mediterranean Station. And as they stay in hospital on an average for four months, this means 74,880 days of illness. This means a considerable loss to the State, as well as a large amount of personal suffering terminated, in some cases after two years’ sickness, by death.

The War Office, Admiralty, and Colonial Office applied in 1904 to the Royal Society of London to undertake a further investigation of this disease. The society sent out a small commission, which has been at work for three years, and has published seven volumes of reports. The problem before the commission was to discover the mode of infection by the Malta-fever germ (the Micrococcus melitensis), and thus, if possible, to arrive at a means of arresting the infection. Various hypotheses, guesses as to probable and possible methods of dissemination, were entertained and examined. As the germ occurs in the blood, it was naturally considered possible that gnats or other insects were the carrying agent. But negative results followed all experiments in this direction. Then it was found that the “germ” passes out of the body in large quantities by the renal secretion, and it was thought that it might be conveyed in a dried form with dust in the air. This also proved to be an incorrect supposition.

Next a very important discovery was made. The germ was found in the blood and the excretions of 10 per cent. of the goats which are kept in Malta as the sole source of milk, and are driven through the streets to supply customers, whilst 50 per cent. of the goats were found to have been infected at some time. Then the germ was found in the milk itself, and it only remained to prove by experiment that it was from the goats’ milk that human beings acquire the infection. A monkey fed with the milk of an infected goat acquired the fever.

The next step was to stop the consumption of goats’ milk by the soldiers and sailors in the hospital and barrack. Actually we were carefully feeding our invalid soldiers and sailors in the great hospital at Valetta with a highly poisonous infected fluid—the milk of the Maltese goat! The preventive measure—the stoppage of goats’ milk—only came into operation in July, 1906. In the first six months of that year there were thirty-one cases of Malta fever in every thousand of the garrison (numbering about 8,000 men). In the preceding six months there had been forty-seven cases per thousand. Now when the goats’ milk was stopped after July, 1906, what was the result? From July to December, 1906, there were only ten cases per thousand of the garrison. In actual numbers there were in July, August, and September in 1905 as many as 258 cases, whilst in the same months in 1906, after removal of goats’ milk from the dietary of the troops, there were only twenty-six cases, and these were probably due to the independent purchase of goats’ milk by soldiers outside the barracks. In the naval hospital until 1906 almost every patient who remained in the hospital a few weeks took the disease. Since the exclusion of goats’ milk not a single case has occurred.

The Director-General of the Medical Department of the Navy reports that there has been no case of Malta fever during the year among the sailors, and only seven cases among the soldiers up to the end of September, 1907.