John Snow, 1813-1858*

LECTURES AND ADDRESSES

JOHN SNOW, 1813-1858*

K. BRYN THOMAS, M.R.C.S., L.R.C.P., F.F.A., R.C.S., D.A. Royal Berkshire Hospital, Reading THERE has been a recent move to re-name the general practitioner, I giving him the more resounding, but nevertheless appropriate title, of 'general physician'. This paper pays tribute to a great general physician, a man well-grounded in the basic knowledge and experience of his profession, who also distinguished himself by developing special interests. Working upon these with the full vigour of a high intellect, he sought to elucidate problems of physiology and path- ology which, in the mid-nineteenth century, were but dimly com- prehended. At the same time, he continued at work in general practice. Indeed, in the circumstances of his time, he could do no else, though he was also able to set up in private practice as an anaesthetist, and at one time was administering 450 anaesthetics in a year. His other interest, cholera, was a subject which he persued with equal avidity, and he expended a prodigious amount of time and energy upon these two subjects, in an all too brief career. He was but 45 years of age at his death. John Snow (figure 1) was born at York on 15 March 1813, the son of a farmer. We have virtually no details of his early life, but at the tender age of 14 he went to Newcastle-upon-Tyne, where he became apprenticed to a surgeon, William Hardcastle. Snow's name appears in the original list of students of the newly formed Newcastle School of Medicine, so that he evidently had opportunities of study at the Newcastle Infirmary. In 1832, when he was 19, he was sent as medical officer to Killingworth Colliery on Tyneside. One wonders how a rather sensitive youth of his years fared in a tough mining community in the 1820's, particularly as he was con- fronted with a raging epidemic of cholera amongst the miners and their families. This led him to a study and knowledge of the disease which he was later to put to good use. At 20, Snow became assistant to a Mr Watson of Burnop Field near Newcastle, and 12 months later he moved to a small village called Pateley Bridge, in Yorkshire, where his chief was a Mr Warburton. Unfortunately, we have no records whatsoever of Snow's medical *From a paper read to the Osler Club of London, 25 May 1967. J. ROY. COLL. GEN. PRACTIT., 1968, 16, 85 86 K. BRYN THOMAS

Figure 1. John Snow. practice in these places, but it is not to be doubted that those years in Durham and Yorkshire were formative in so far as concerned his general knowledge of medicine. In 1836 Snow decided to become a student in London. Travelling from northern parts in those times was always something of an adventure and Snow undertook a long pilgrimage, journeying on foot via Liverpool, through North and South Wales, staying at Bath with an uncle, and thence on to London, where he enrolled as a student in the Hunterian School of Medicine in Windmill Street. In 1836 this famous school (founded by William Hunter almost a JOHN SNOW, 1,813-1858 87 century btfore) was nearing the end of its days. Indeed there is some discrepancy in the dates, for Teacher in his notes on William Hunter, says that the school closed in 1833; there are however, advertisements in The Lancet for 1836 for a Hunterian Theatre of Anatomy in Little Windmill Street. Certainly by this time most students preferred to undertake their anatomy at St. George's or the Middlesex hospitals, and the last proprietor of the Hunterian School, Herbert Mayo, became professor of anatomy at King's College in 1830. A year later Snow became a student at the school attached to Westminster Hospital, then newly moved into the building in the Broad Sanctuary, opposite the Abbey, which some of us will remem- ber. In October, 1837, he became M.R.C.S. and in 1838 a member of the Apothecaries' Company. Then, as he himself is stated to have said, he "nailed up his colours" at 54, Frith Street, Soho (a house whose site is now occupied by a firm of shampoo makers), 200 yards away from the famous water pump, and from what is now the John Snow public house (opened as such in 1958-an unusual memorial for one who was a staunch, even bigoted, teetotal- ler!). After an abortive attempt to get on to the staff of the West- minster, Snow attended clinical classes at the new Charing Cross Hospital, where he afterwards became a physician to the outpatient department. In 1843 he took the M.B., of the University of London, proceeding M.D. in the following year. At this period too, Snow became a member of the Westminster Medical Society, later incorporated into the Medical Society of London. He was described as being at first, a tentative speaker, but he made friends, and in 1850 was President of the Society, to which he read several of his early papers. These indicate clearly to us the scientific bent ofhis mind. Among these papers we find what may be described as precursors ofhis anaesthetic investigations; for example, a very interesting paper on "Asphyxia and the resuscitation of new- born children".' There are also papers of general practice interest such as one on phosphatic calculi,2 and another on a case of "strangulation of the ileum",3 in which the internal strangulation found at autopsy was described as being due to a congenital band, associated with the appendix which was not inflamed. The former paper was read at a first sessional meeting in 1841 of the Westminster Medical Society at the rooms of the Ethnological Society in 27 Sackville Street. A report states "the attendance of members was numerous and the very greatly increased comfort and accommodation offered at the new place of meeting gave great satisfaction." But it was in Soho that occurred an event which has probably been over-emphasized, though the affairs which led up to it were dramatic enough, if one cares for that sort of drama. This was the business of the Broad Street pump. 88 K. BRYN THOMAS Whereas to anaesthetists Snow is known for his pioneer' work on ether, chloroform and other anaesthetics, to the epidemiologist he is known for his even more important work on the mode of transmis- sion of cholera. If we consider the matter in terms of lives saved, then we must regard John Snow's work on cholera and his impact on public health and hygiene to warrant even higher praise than his efforts in the field of anaesthesia, however much this may have influenced later workers. Certain it is, that this one man's contribu- tion on the one hand to life-saving hygienic method, and on the other, to the reduction of pain at operation, mean that we should think of him in the same terms as Pasteur, Koch and Lister as one of the great benefactors. A letter to the Editor of the Times shows the horror in the background of the Soho story. The authors were 56 men and women of that-district, and the letter was published in 1849 in its original state of spelling. To the Editur of the Times Newspaper Tues. July 3 1849 Sur, May we beg and seek your protekshun ... We Sur livin in a wildiness, so far as the rest of London knows anything of us, or as the rich and great people think about. We live in muck and filth. We ain't got no privies, no dust bins, no drains, no water-splies, and no water or suers in the hole place. The stench of a Gully-hole is disgustin. We all of us suffur, and numbers are ill, and if the cholera comes Lord help us. Some gentlemans come round yesterday, and we thought they was from the Suer Company, but they was complaining of the noosance and stench our lanes and cortes was to them in New Oxford Street. They was much surprised to see the seller in 12 Carrier Street, where a child was dying from fever, and would not believe that sixty persons sleep in it each night. This here seller you couldn't swing a cat in, and the rent is five shillings a week. There are great many sich deare sellers . . . Praye Sur come and see us, for we are livin like Piggs and it ain't fair we should be so ill-treated. We are your respeckfull servants in Church Lane, Carrier Street and the other Corts, John Scott (and 55 others) These unfortunate people, living in squalor and filth, were the patients of doctors such as Snow, and their numbers were multiplied many thousandfold throughout London, and indeed in all the major cities of the Western World. Asiatic cholera was first imported into Europe in 1832, and many cities and towns again were subjected to frightening visitations of the disease in 1849 and 1854. At this time there was no knowledge of the causation or spread of the disease, and Robert Koch's discovery of the vibrio of cholera was not to come till 1883. Even then there was disbelief. Pettenkoffer's famous self-experiment, when he JotiN SNow, 1813-1858 89 drank a decoction from the Nile in order to prove his point, will be recalled. We have seen how, early in his career, (he was under 20), Snow was plunged into an epidemic of cholera among the Durham miners. This experience was one not lightly forgotten, and several times in his books and papers he refers to the spread of the disease in the in- sanitary conditions of the times, where a worker spent long hours underground, so that, if he became infected, his excretions rapidly contaminated his fellows. Snow began speaking on cholera in 1849, and in this same year he published his book On the mode of communication of cholera,4 with a second edition in 1855, the year after the Broad Street episode. This first communication read to the Westminster Medical Society on 13 October 1849, shows him inveighing against lack of personal cleanliness (this was not new) and, more important, illus- trates that he was at this time already incriminating drinking water as the communicating medium for the disease. Had Snow's views then prevailed, London might have been spared the further visits of the disease, but unfortunately there were still those who believed it to be airborne or spread by the fomites, and there were many who only half-heartedly accepted Snow's views, believing that the presence of water increased the prevalence of the disease, as in the case of malaria. So convinced were the authorities of the airborne theory that one finds a reference to Galway, where in 1849 there had been 840 cases with 320 deaths, a 38 per cent mortality. The authorities-states the report-have hit on a novel way of getting rid of the disease. The 68th Regiment yesterday fired at the Square, Galway, 20 rounds of blank cartridge each rank and file, at the express desire of the local authorities, for the purpose of purifying the air and expelling the cholera. But John Snow had other ideas. Throughout the early 1850's he kept hammering away, and when cholera struck in his own area in 1854 he knew what to do. He rapidly took stock of the situation, as we see from his map (figure 2). Within a few hundred yards of the pump on the corner of Broad (now Broadwick) Street, and Cambridge (now Lexington) Street there occurred some 500 cases of cholera in three days. Snow's survey showed this pump to be at the centre of the infection, while other nearby areas, supplied by other pumps, were not infected, or minimally so. Snow also noted the brewery in Broad Street, where the brewers were not infected. They drank beer! There was too, the lady in Hampstead who thought, misguidedly as it turned out, that the Broad Street water was so superior that she had bottles supplied to her, and who died as a result of her innocent belief. Snow wrote persistently to the journals on the matter: one quota- 90 K. BRYN THOMAS

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Figure 2. Distribution of cases of cholera in relation to the Broad Street pump (arrowed, centre). Map by John Snow 1854. tion is given as an example of his direct approach to the problem: The pump well in Broad Street is from 28-30 feet in depth and the sewer which passes a few yards from it, is 22 feet below the surface. This sewer proceeds from Marshall Street, where some cases of cholera had occurred before the great outbreak. I am of opinion that the contamination of the water of the pump-wells of large towns is a matter of vital importance. Most of the pumps in this neigh- bourhood yield water that is very impure: and I believe it is merely to the accident of the cholera evacuations not having passed along the sewers nearest to the wells that many localities in London near a favourite pump have escaped a catastrophe similar to that which has just occurred in this parish.5 Snow wrote at least 16 other papers on the prevention of cholera, and his recommendations to the Board of Guardians in Soho to remove the pump handle was fortunately acted upon. The epidemic JoHN SNow, 1813-1858 91 thereupon subsided, at least in this area. But pumps were not the only source of water. There was also the Thames, and Snow showed by a meticulous investigation that the areas supplied by water from the Southwark and Vauxhall water company, and obtained from the faecal-laden Thames, were infected 12 times more severely than those areas supplied by the Lambeth Company, whose water came from the purer regions of Thames Ditton. Snow called on every house in the area to find out where their water came from. Finding that the occupants were never able to tell him, he devised a chemical test (using silver nitrate) which flocculated the impure water of the Southwark and Vauxhall Company! The table shows Snow's figures, in which one may note the high mortality associated with the water supplied by this Com- pany. TABLE

Deaths by cholera in Deaths in Population 14 weeks 10,000 in 1851 ending living October 14 London ...... 2,362,236 10,367 43 West districts ...... 376,427 1,992 53 North districts ...... 490,396 735 14 Central districts ...... 393,256 612 15 East districts ...... 485,522 1,461 30 South districts ...... 616,635 5,567 90 Houses supplied by Southwark and Vauxhall Company .. .. 266,516 4,093 153 Houses supplied by Lambeth Company ...... 173,748 461 26 John Snow's figures for cholera in various districts. Note the difference between the two water suppliers. Subsequent developments in public health and sanitation were to relieve London permanently of such epidemics, but Benjamin Ward Richardson at the British Medical Association meeting in Birmingham in 1856, was to say It is well-known that the discovery of the connection between cholera and water supply in no way belonged to the Board of Health, but exclusively to one of our associates, Dr John Snow ... who ... contended, in regard to epidemic disorders . . . that these have a specific poison, which is propagated by certain fixed laws, which attains its progression and increase in and through animal bodies... which is communicated from one animal body to another, and which is the same in essence from first to last.... Smallpox ... would never appear.. in the absence of its specific poison ... .6 Though these views met with little contemporary support, this was Snow's belief as a precursor of Pasteur. 92 K. ]BRYN THOMAS Snow's work on cholera and public hygiene was only a part of his activities at this same time. In 1846, the introduction of ether as an anaesthetic agent was an event which startled and fascinated the medical world. We do not know how he first became interested, but with his scientific background and bent, Snow was soon at work investigating the properties of the new wonder drugs, and making apparatus for their administration. There is not much evidence that, at first, he had the opportunity to use these on patients, though it was not long before anybody who had any pre- tensions took to 'etherizing'. The story is that Snow, finding a chemist's assistant busily administering ether decided that he himself could do it more efficiently. He therefore applied for permission to give anaesthetics in the outpatient dental department at St George's Hospital, where his administrations were so successful and efficient that he moved into general surgery and soon came to the notice of Robert Liston, the University College Hospital surgeon who had performed the first major operation under ether, in this country, on 19 December 1846. Liston was responsible for Snow's admission to University College Hospital and they worked together until Liston died later in 1847. In the meantime, James Young Simpson had produced chloroform in January 1847, and Snow took up this anaesthetic also. His inventive and scientific genius-is shown by his early pieces of apparatus, and more so perhaps by his appreciation of the physiology and signs of anaesthesia, so well described in his book, On ether published in 1847. He was essentially practical, and Richardson relates that on one occasion, Snow stated that ether was a safer anaesthetic than chloroform. Asked why he then used the latter, in preference, he replied "for the same reason that you use phosphorus matches instead of the tinder box. An occasional risk never stands in the way of ready acceptability" (figures 3, 4). Snow's most famous patient was Queen Victoria. He had been consulted prior to the birth of Prince Arthur in 1850, but was not actually called. On 7 April 1853 when Prince Leopold was born, he gave chloroform to Her Majesty, who expressed herself as greatly relieved by %he administration. Snow recorded in his diary that the chloroform was given on a handkerchief in 15 minim doses, and the administration lasted 53 minutes. This occurrence had a profound and lasting effect on public opinion. We recall James Young Simpson's dramatic struggle in 1847-48 against those who tried to maintain the scriptural precept "in sorrow shalt thou bring forth children." Six years later there were still those who sought to impose their bigotry upon a public who were becoming more and more enlightened in their demands for anaesthesia for parturient women. Chloroform a la reine provided a very necessary corrective and encouragement. Even so, there were qualified men who were far from being convinced, though on other grounds. Among these JOHN SNOW, 1813-1858 93

Figure 3. Snow's ether apparatus 1847.

Figure 4. John Snow's facepiece chloroform inhaler. (Left). Exterior view. In the back wall, the perforated cap of the inspiratory valve; above, the orifices of the two air-inlet tubes. In the roof, the expiratory valve. On the side wall, a funnel for replenishing the sponge within with chloroform. (Right). Interior view. In the back wall, the flap of the inspiratory valve; above, the two air-inlet tubes. In the roof, the orifice of the expiratory valve. From the floor rise two wires to support a sponge. The circular depression in the floor presumably caught surplus liquid chloroform (so long as administration was made with the patient in the sitting position). 94 K. BRYN THOMAS was the firebrand Thomas Wakley, editor of The Lancet, who inveighed in heavy terms against those who had dared to allow chloroform to be given to Her Majesty. Intense astonishment has been excited throughout the profession by the rumour that Her Majesty during her last labour was placed under the influence of chloroform, an agent which has unquestionably caused instantaneous death in a considerable number of cases. We could not imagine that anyone had incurred the awful responsibility of advising the administration of chloroform to Her Majesty during a perfectly normal labour with a seventh child. Let it not be supposed that we would undervalue the immense importance of chloroform in surgical operations . . . its unnecessary inhalation involves an amount of responsibility which words cannot describe. Lancet, Editorial, 14 May 1853. And the editor adds that he is thankful to hear a report that the Queen was not rendered insensible by chloroform. This is probably literally true, though Wakley may not have realized it. Snow knew of the analgesic effect of chloroform in a conscious patient, and was capable of maintaining such a state. His dosage-15 minims- would almost certainly maintain analgesia, rather than anaesthesia. Snow, unperturbed, continued to produce paper after paper on chloroform, ether and other anaesthetics and their effects, and his two great books, On ether7 and On chloroform8 epitomized contemporary knowledge, and were not superseded till late in the century. Snow's personal life does not obtrude itself upon the story of his scientific and medical pursuits. His biographer, Richardson, describes him as reserved and rather lonely, but with a dry sense of humour. He did not marry, and his early death at the age of 45, robbed British medicine of one who, had he lived, would have continued to imprint his mark upon the scientific developments of his time. REFERENCES 1. Snow, J. (1841). Lond. med. Gaz. 29, 222. 2. Snow, J. (1846). Lond. med. Gaz. N.S. 3, 877. 3. Snow, J. (1846). Lond. med. Gaz. N.S. 3, 1049. 4. Snow, J. (1849). On the mode of communication of cholera. London. Churchill. P. 31. 5. Snow, J. (1854). Med. T. and Gaz. 9, 321. 6. Richardson, B. W. (1856). Ass. med. J. 4, 683. 7. Snow, J. (1847). On the inhalation ofthe vapour ofether in surgical operations. Containing a description of the various stages ofetherization. London. Churchill. P. 88. 8. Snow, J. (1858). On chloroform andother anaesthetics. Edited with a memoir of their author by Benjamin W. Richardson. London. Churchill. P. 487.