Dr. Ian Carr

Professor Emeritus, Faculty of Medicine, University of Manitoba

The founder of pathology was Giovanni Batista Morgagni (1682-1771), professor of medicine and anatomy at Padua for 56 years. He published at the age of 79 the De Sedibus Causis Morborum containing accounts of aneurysm, acute yellow atrophy of the liver, heart block and valvular disease of the heart, pneumonia and the connection between miliary disease and cerebral abscess. He detailed the case histories and pathological appearances of no less than 700 cases.

A man who had been too much given to the exercise of tennis and the abuse of wine, was, in consequence of both these irregularities, seized with a pain of the right arm, and soon after of the left, joined with a fever. After these there appeared a tumour on the upper part of the sternum, like a large boil. The patient came into the Hospital of Incurables, at Bologna ... in the year 1704. The swelling on ...the chest wall was equal in size to a quince...and began to exsude blood in one place ... very near having broken through the skin ... He (being quite ignorant of the danger which was at hand) began to pull off the bandages, for the sake of showing his disorder. But his circumstance being observed, he was prevented going on, and ordered to keep himself still, and to think seriously and piously of his departure from this mortal life, which was very near at hand, and inevitable. On the day following, he felt the blood gushing forth, and had the presence of mind not only to commend himself to God, but to take up with his own hands a basin that lay at his bed-side; and, as if he had been receiving the blood of another person, put it beneath the gaping tumour, while the attendants immediately ran to him as fast as possible, in whose arms he soon expired.

On examining the body before I dissected it, I saw that there was no longer any tumour, inasmuch as it had subsided after the blood, by which it had been raised up externally, and had been discharged. The skin was there broken through, and the parts that lie beneath it with an aperture, which admitted two fingers at once....In both the cavities of the thorax, also, was a great quantity of water, of a yellowish colour. And there was a large aneurism, into which the anterior part of the curvature of the aorta itself being expanded, had partly consumed the upper part of the sternum, the extremities of the clavicles which lie upon it, and the neighbouring ribs, and partly had made them diseased, by bringing on a caries.

Morgagni had no microscope. Microscopes were needed for further advance in pathology. Marcello Malpighi (1628-1694) of Bologna saw capillaries in the frog's lung and completed Harvey's discovery of the circulation. He also saw the layers of the skin, white pulp of the spleen and renal glomeruli. Athanasius Kircher (1602-1680) studied the blood of plague patients and saw countless masses of small worms - red blood corpuscle. He described striations in muscle fibres, bacteria and protozoa. Rudolph Virchow (1821-92) brought the microscope to pathology and showed that cell changes were the centre of the alterations of the tissues in disease. Omnis cellula e cellula.

The next steps were the demonstrations that disease was caused by micro-organisms, and that immunity could be provided. In 1835, Bassi showed that a disease of silk worm was due to a fungal infection and in 1839 Schonlein showed that a human skin disease, favus, was due to a fungal infection. The man who revolutionised our understanding of disease by finding bacterial causes was Louis Pasteur (1822-95). Pasteur was a French microbiologist who made his name initially investigating a disease of silkworms.

Pasteur described his great discovery, immunization against rabies:

The ethical implications are evident; the lesson --- medical ethics change.

We owe clean surgery to Joseph Lister (1827-1912) who after training in London and Edinburgh in 1860 became professor of surgery at the Royal Infirmary, Glasgow. Patients then faced danger equal to the battlefield when they went into the operating theatre. Lister had read Pasteur's papers and came to the conclusion that wound sepsis and putrefaction in wine were similar processes. He therefore applied phenol (carbolic acid), a potent antiseptic, directly to wounds and sprayed it into the air. He tried out his new treatment on compound fractures, saving 9 of 11 limbs, losing only one patient. Prior to this time compound fractures necessitated amputation and were often fatal.

Two of Lister's dressers (assistants) Blanchard and Chown were pioneer Winnipeg surgeons.

By 1870, Pasteur had proven the microbial aetiology of bacterial diseases in silkworms. Pasteur's German rival contributed equally to the development of bacteriology. Robert Koch (1843-1910) was a family physician, who stimulated by clinical experience of an outbreak of anthrax, began to investigate its aetiology.

Koch developed what have become the standard techniques for culture of bacteria, in particular the use of solid agar media. By these he demonstrated that a specific sporing bacillus was the cause of anthrax, and in 1882 demonstrated the cause of tuberculosis. The criteria which he used for proof of bacterial aetiology are now known as Koch's postulates.

To prove that tuberculosis ...is caused by invasion of bacilli and the growth and multiplication of bacilli, it was necessary to isolate the bacilli from the body; to grow them in pure culture...; and, by administering the isolated bacilli to animals, to reproduce the same morbid condition....

In 1885, Koch became Professor of Hygiene in the University of Berlin, from which in 1890, he announced his discovery of tuberculin, at first a secret formula, and later described as a glycerin extract of tubercle bacilli. He believed at first that this would prove effective in the treatment of human tuberculosis; amid much controversy, this proved not to be so.

The treatment of tuberculosis remained unsatisfactory ; patients were isolated for long periods in sanatoria, in conditions which were at once rigorous and non-specifically favourable. In the 1920's a vaccine, BCG came into use in the prevention of childhood tuberculosis; streptomycin was discovered in 1943. The techniques evolved by Pasteur and Koch and elaborated by many others, led to the proof of the bacterial cause of much human disease during the subsequent fifty years.

The idea that there were smaller infective agents than viruses came from work on the mosaic virus of the tobacco plant, which was proved to pass through a fine filter, by Mayer and Ivanovski working separately over the ten years from 1886. Extensive proof of the viral aetiology of human disease depended on the development of satisfactory techniques for tissue culture in the early part of the twentieth century.

Anaesthesia started in North America. Various potions including opiates and alcohol have been used since ancient times to dull pain and lull into sleep. The hypnotic effect of ether, "sweet vitriol," has been known since the sixteenth century, but the first effective anaesthetic dates back only to 1842.

In that year Crawford Long, a physician in the small town of Jefferson, Georgia noticed that when people inhaled ether as a "recreational" drug, they became insensitive to pain. He removed a tumour from a patient's neck under ether anaesthesia, but did not immediately publicize his discovery. Two or three years later others, Wells, Morton and Jackson tried first nitrous oxide then ether for first dental and then other purposes. Over the years Congress voted $100,000 to the inventor of anaesthesia; but there was profound disagreement as to who the inventor was.

Long wrote some time later:

The discovery soon crossed the Atlantic and was first used in the University College Hospital, London, 1846. It was followed a year later by chloroform introduced in Edinburgh by James Young Simpson.

Up until 1800, human communities existed with very little control of public health. There were some municipal regulations against the disposal within towns of sewage and garbage and during plagues municipal officials were appointed to seek out cases, but there was little organization or enforcement. Cities of the European Industrial Revolution were overcrowded and had poor water supplies. In the early nineteenth century, over half a million people in London got their water from stand pipes in the street. Excrement was discharged into open sewers. Epidemic cholera and typhoid were frequent and the rates of morbidity and mortality among the general population, and especially among infants were high. These things happened early in England, which was an early country to industrialize. Poor relief cost so much that a number of Royal Commissions were set up to look into various public health matters. These investigations were supported by the leading humanitarians of the day, notably a lawyer named Edwin Chadwick, who led the agitation for control of public health. This started in Britain with the 1848 Public Health Act. There was a major epidemic of cholera in London in 1854; Dr John Snow demonstrated that many cases occurred among people who drank water from a pump in Broad Street; those who obtained water from other pumps did not contract the disease. The pump handle was removed and in that area there were no more cases of cholera. When adequate water supplies and sewage systems were installed and slums were cleared, the epidemics abated. John Snow was also a pioneer in surgical anaesthesia.

Smallpox was the most virulent of the infectious diseases, with a mortality rate well over 50% in previously unexposed populations. Attempts at prevention were made in the early eighteenth century by inoculation with pus from active cases of smallpox. This process, variolation, was often effective, but was lethal in a significant proportion of patients.

Edward Jenner (1749-1823), a Gloucestershire physician, observed that local country people believed that those who had had cow-pox would not contract small-pox. Jenner vaccinated a boy James Phipps with material taken from a cow-pox vesicle on the hands of a dairy maid and then showed that the boy was immune to small-pox.

The practice spread within two years and by the time of Jenner's death in 1823 was being used in many countries around the world.

Morgagni, G. De sedibus, et causis morborum per anatomen indagatis libri quinque. Dissectiones, et animadversiones, nunc primum editas complectuntur propemodum innumeras, medicis, chirurgis, anatomicis profuturas. Venetiis: Ex Typographia Remondiniana, 1761.