Pathology is the study of the causes, processes and effects of disease. In practical terms, pathology is often studied by the examination of bodily tissues within the laboratory setting. It comprises four principal subjects of enquiry – the cause of an illness (its aetiology), how it develops (pathogenesis), how cell structure is changed, and how the disease manifests itself.
The great pioneer of pathology was a German, Rudolf Virchow (1821–1902), who ushered in the era of ‘microscopic pathology’ by focusing on disease studied at the cellular level (histopathology). As Rubin’s Pathology, a standard textbook on the subject, tells us: ‘In the 19th century, Rudolf Virchow, often referred to as the father of modern pathology, proposed that injury to the smallest living unit of the body, the cell, is the basis of all disease. To this day, clinical and experimental pathology remain rooted in this concept.’
Virchow inspired a new generation, among them his student Julius Cohnheim, whose innovations included the freezing of materials prior to examination, and Friedrich von Recklinghausen (1833–1910), who published major studies on, for example, thrombosis, embolism and infarction. The 20th century was a period marked by a rapid succession of new discoveries. The work of Karl Landsteiner (1868–1943), for instance, laid the groundwork for modern blood typing. Meanwhile, technological advances – in, for example, microscopy and image processing – have ensured that pathology today is perhaps developing more quickly than ever before.
The primitive post-mortem
Although figures such as Hippocrates and Galen made efforts to understand the basic pathology of disease, the Arabian physician Avenzoar (1091–1161) is believed to have been the first to carry out a post-mortem dissection to establish the cause of a specific ailment (specifically, identifying a parasite as the cause of scabies). This was in stark contrast to the more usual reason for dissection: to gain a better understanding of the functions of the un-diseased body.
An Italian, Antonio Benivieni (1443–1502), then developed the idea of the autopsy as a means to establish an individual’s cause of death. In 1761, another Italian, Giovanni Morgagni, published De Sedibus et Causis Morborum per Anatomem Indagatis (On the Seats and Causes of Disease), detailing his findings from some 600 autopsies, so cementing the relationship between illness and anatomical examination. Marie François Xavier Bichat (1771–1802), an army surgeon, then took the opportunity to examine bodies freshly retrieved from the guillotines of the French Revolution, so vastly expanding our understanding of the pathology of several diseases. Another Frenchman, Gabriel Andral, built upon and extended Bichat’s work, publishing his two-volume Précis d’ Anatomie Pathologique in 1828.