MANSON, PATRICK

(b. Old Meldrum, Aberdeen, Scotland, 3 October 1844; d. London, England, 9 April 1922) tropical medicine.

Manson was born at Cromlet Hill, Old Meldrum, in Aberdeenshire, the second son of a family of five sons and four daughters. His father, John Manson, was a bank manager and a local laird. His mother, who exercised a profound influence upon him up to the time of her death at the age of eighty-eight, was Elizabeth Livingstone, a distant cousin of David Livingstone the explorer, and a member of a well-known local family named Blaikie.

In his youth Manson was considered rather dull by his teacher, who complained that he spent too much of his time shooting partridges and rabbits and too little on classical education. At the age of eleven he shot a savage cat and “extracted from its innards a long tapeworm,” his first practical exercise in parasitology.

In 1857 the family moved to Aberdeen, where Patrick attended the Gymnasium and the West End Academy. His mother’s family owned a large engineering works in the city, to which, at the age of fourteen, Manson became apprenticed. He undertook the heavy work so enthusiastically that he developed curvature of the spine and a partial paresis of the right arm, which for the next six months forced him to spend most of each day lying on his back. Nevertheless, for two hours daily he contrived to study natural history at Marischal College, which so stimulated his interest in science that, upon learning that his work would count as part of the medical curriculum, he decided not to return to engineering but to devote his life to medicine.

He became a student at the Aberdeen Medical School in 1860, graduated M.B., C.M., in 1865, M.D. in 1866, and as his first appointment became assistant medical officer at the Durham County Mental Asylum. He remained in Durham for only a year. Persuaded by his elder brother, then working in Shanghai, to travel overseas, he obtained the post of medical officer for Formosa in the Chinese Imperial Maritime Customs, where his official duties were to inspect ships calling at the port of Takao (now Kaohsiung) and to treat their crews. Of this work he kept a careful diary now preserved at Manson House in London, in which he made detailed descriptions of cases of elephantiasis, leprosy, and “heart disease” — which he later recognized as beriberi. At the end of 1870 he unwittingly became involved in the political struggle between China and Japan, to escape from which, on the advice of the British consul, he left Formosa early in 1871 and settled at Amoy on the mainland of China.

His private practice there and his post at the Baptist Missionary Hospital provided him with an immense number of cases that added greatly to his experience. His special interest in elephantiasis led him to devise surgical procedures for removing the masses of tissue associated with the disease, of which, it is recorded, he removed over a ton in a period of three years.

At the end of 1874 Manson returned to Great Britain on a year’s leave, during which he was married to Henrietta Isabella Thurburn on 21 December 1875. He spent much of his leave searching the libraries for literature on elephantiasis, in the course of which, on 25 March 1875, while working in the British Museum, he came across the work of Timothy Lewis, a surgeon in the Indian Army Medical Service, on Filaria sanguinis hominis (F.S.H.). Lewis was convinced that F.S.H. was the immature form of a much larger adult worm, which he eventually discovered in 1877, some nine months after its discovery by Thomas Lane Bancroft in Australia. He also believed that the microfilariae or the adult worms were the causative agents of disease, although nothing was known of the method of transmission. Manson pondered long on these discoveries of Lewis, and from them he formulated his theory of mosquito transmission. So great was his interest that upon his return to Amoy he devoted all his spare time to investigating the correctness of his theory.

To this end he enlisted the assistance of two medical students to examine blood for the presence of F.S.H. One of the students could work only at night, and Manson noticed that a significantly higher proportion of positives was obtained by this “night observer” than by the day worker. From this observation he stumbled upon the hitherto unsuspected phenomenon of microfilarial periodicity. By training two men whose blood contained microfilariae to examine each other every three hours for six weeks, he was able conclusively to demonstrate that microfilariae were present in the blood in larger numbers at night than during the day. (The resulting graphs of microfilarial numbers are now preserved in the London School of Hygiene and Tropical Medicine.) He also demonstrated that the microfilariae were surrounded by a sheath, from which they could escape when the blood was cooled in ice. This observation led him to postulate that F.S.H. was an embryo worm that could continue its development outside the human body in the common brown mosquito of Amoy (now identified as Culex fatigans). He then persuaded his gardener, who was infected with microfilariae, to allow large numbers of mosquitoes to feed upon him; and by dissecting the fed mosquitoes he was able to trace the development of the worm through the intestine and into the thoracic musculature. In his publications of 1877 and 1878 Manson referred to the mosquitoes as “nurses.”

His work, however, was greatly hampered by the absence of literature on the life cycle of mosquitoes. He mistakenly believed that mosquitoes took only a single meal of blood, with the result that most of his mosquitoes died within five days. He also erroneously believed that man became infected by ingesting the larvae in water, into which they were released when the mosquitoes laid their eggs.

Nevertheless, these early experiments provided the first proof of the obligatory involvement of an arthropod vector in the life cycle of a parasite. The almost unending list of parasites now known to require an arthropod as a necessary alternate host is testimony of the fundamental nature of Manson’s concept. Yet, when his work on periodicity and on development in the mosquito was presented to the Linnean Society of London by the president, Spencer Cobbold, on 7 March 1878, the only recognition that it received was incredulity and ridicule.

Manson’s part in the elucidation of the transmission of malaria by mosquitoes took place some sixteen years later. In 1890, under financial pressure caused by depreciation of the Chinese dollar, he set up practice in London and was appointed physician to the Seamen’s Hospital, where he had access to many cases of tropical disease. He carried out prolonged observations on the “exflagellation” of malaria and, in a paper published in 1894, postulated that the process was a normal part of the life cycle of the parasite in the stomach of the mosquito. In the same year he met Ronald Ross, with whom, after showing him the malaria parasite, he spent long hours discussing the mosquito-malaria theory. Largely as a result of pressure on the India Office brought to bear by Manson, Ross was dispatched to India the following year to investigate the theory. Manson’s advice was to “follow the flagellum,” and Ross soon succeeded in observing exflagellation in the stomach of the mosquito. But the problem of following the parasite into the tissues of the mosquito, of which only one species is suitable for development, proved to be a Herculean task. Throughout the months of investigation that followed, Manson maintained a continuous correspondence with Ross, much of which has now been published. In August 1897 Ross dissected a new type of mosquito (Anopheles) that had fed on a malaria patient, and in it he found pigmented round bodies on the stomach wall. The pigmented bodies were sent to Manson, who confirmed their significance. Soon afterward Ross was removed to an area where human malaria was absent, and there he applied himself to the study of Proteosoma, a malaria parasite of sparrows. From this study he was able in 1898 to describe its complete life cycle in the mosquito. The discovery was announced by Manson at a meeting of the British Medical Association in Edinburgh. Ross fully acknowledged the part played by Manson; but Manson, with characteristic modesty, disclaimed any credit save that of having “discovered” Ross. Meanwhile, in Italy, Grassi in 1898 transmitted human malaria by the bite of a mosquito and in 1901 described the complete life cycle of the parasite.

Manson was responsible not only for the concept of the mosquito-transmission theory but also for bringing the findings of Ross and Grassi to the attention of the public and thus for spreading the knowledge that eventually led to the practical control of malaria. In 1900, from a consignment of infected mosquitoes sent by Grassi to London, Manson succeeded in infecting his son and a laboratory technician by mosquito bite. In the same year Manson sent two of his pupils, Low and Sambon, to live for three months in a highly malarious area of Italy. By the simple expedient of spending each night in a mosquito-proof hut, they remained healthy and uninfected, while their neighbors lay sick and dying of the disease. Manson was involved in the whole field of tropical medicine, as well as in the discovery of many other pathogenic parasites and in the elucidation of their life cycles, including Paragonimus westermanni, Sparganum mansoni, Schistosoma mansoni and S. japonicum, Oxyspirura mansoni, Loa loa, and Filaria perstans.

Manson was a man of deep penetrative mind, original in thought, creative in imagination, careful and patient in experimentation. He was possessed of an overwhelming desire to communicate his knowledge to others, and so stimulating was his enthusiasm that wherever he went he invariably gathered about him a group of eager students. He played a significant part in the foundation of the College of Medicine at Hong Kong (later to form the basis of the University of Hong Kong) and became the first dean. In a letter to Lancet published in 1897 he stressed the need for special training of doctors destined for work in the tropics. Despite the disapproval of many of his colleagues, his recommendations led to the foundation of the London School of Tropical Medicine in 1899, some six months after the opening of the world’s first tropical school in Liverpool. On many subsequent occasions Manson pleaded for funds for “our tropical schools,” which became the models for similar institutions throughout the world. Tropical Diseases. A Manual of the Diseases of Warm Climates (1898), his principal work, is now in its seventeenth edition and has become a classic textbook of tropical medicine. He taught continually at the London School of Tropical Medicine and its nearby hospital until his retirement in 1914. He was elected a fellow of the Royal Society in 1900, received a knighthood in 1903, and was medical adviser to the Colonial Office for nearly twenty years. In 1907 he was one of the founders of the Royal Society of Tropical Medicine and was elected its first president. After his retirement he spent most of his time fishing in Ireland, interspersed with visits to Ceylon, Rhodesia, and South Africa. The last of his frequent visits to the London School took place only two weeks before his death at the age of seventy-seven. He is buried in Aberdeen.

BIBLIOGRAPHY

A series of articles in commemoration of Manson’s life and work, including a short autobiography, appeared in Journal of Tropical Medicine and Hygiene, 25 (1922), 155– 206; see also the bibliography of his writings compiled by S. Honeyman, ibid., 206–208. See also the obituaries in Lancet (1922), 767–769; Proceedings of the Royal Society, 94 (1922), xliii-xlviii; and Transactions of the Royal Society of Tropical Medicine and Hygiene, 16 (1922), 1–15; and the article by J. W. W. Stephens in Dictionary of National Biography 1922–1930 (London, 1937), 560–562.

Full-length studies of Manson’s life and work are Phillip Manson-Bahr, Patrick Manson, the Father of Tropical Medicine (London-New York, 1962); P. Manson-Bahr and A. Alcock, The Life and Work of Sir Patrick Manson (London, 1927); and Ronald Ross, Memories of Sir Patrick Manson (London, 1930).

M. J. Clarkson

MANSON, PATRICK

Patrick Manson (1844–1922), the man identified as the "father of tropical medicine," was an Aberdonian Scot who studied medicine in his home city of Aberdeen and in Edinburgh. Following his graduation in 1865, he went straight into the Chinese Imperial Maritime Customs Service, first in Formosa and later in Amoy. His work in China covered a remarkable range and included many original discoveries about the causes and suitable control measures for some of the tropical diseases that were so common at that time. This included work on several intestinal parasites; skin diseases caused by fungus infections; and tropical sprue, a debilitating bowel disease that causes or is associated with vitamin and mineral deficiencies.

In 1877, Manson discovered that the crippling disease known as elephantiasis was caused by a filarial worm and transmitted by mosquitoes—the first demonstration that mosquitoes transmitted diseases. After returning to Britain in 1890 he established a consultant medical practice in London and became a medical teacher and adviser to the British Colonial Office. His work included the reorganization of the West African medical services. In 1898 he published a seminal work, Tropical Diseases, and in 1899 he founded the London School of Hygiene and Tropical Medicine. Previously, he had founded a school of tropical medicine in Hong Kong.

Manson influenced a whole generation of British medical scientists who studied and specialized in tropical diseases. The greatest of these was Ronald Ross, to whom he passed on his hypothesis that mosquitoes must be the vector that transmitted malaria. Manson's name is immortalized several times in the taxonomy of the pathogens he identified. He received many honors and awards, including a knighthood.

John M. Last

(see also: Tropical Infectious Diseases; Vector-Borne Diseases )