The vanishing link between animalcules and disease before the 19th century.

When Antoni van Leeuwenhoek began his work with microscopes in the late 17th century, western medicine was mostly based on the work of a Roman doctor called Galen (129-199 ad), theological interpretation, superstition, and folk remedies. During modern discussions of Van Leeuwenhoek's work, a common question from listeners is why it took so long for the link between Van Leeuwenhoek's discoveries and infectious disease to be accepted. Published literature, examples of which are discussed here, shows that many researchers, doctors, and others reported the link, even during Van Leeuwenhoek's lifetime. However, it was frequently not taken seriously by the most influential people. The scientific establishment included a faction of the Royal Society of London who called themselves the 'Mechanical Philosophers'. They ridiculed those reporting animalcule-linked infection, dismissing them as 'Contagionists'. The medical establishment also included many influential people with a lot to lose if they changed their established approaches, and many quack doctors. Most religious ministers were strongly orthodox, some even claiming that helping the sick angered God. A major problem, of course, was that technology and biological understanding also lagged far behind. Despite the fact that the use of vaccination was under active discussion in the Royal Society at the time of Van Leeuwenhoek's death and quarantine was in regular use, a possible microbial connection was apparently not considered. It was not until late in the 19th century, that Robert Koch (1843-1910) isolated Bacillus anthracis, proved that it caused anthrax, and was believed. This paper follows a lecture given during the online Microbe Forum in June 2021, and illustrates the difficulties of establishing the true link between Van Leeuwenhoek's animalcules and infectious disease in humans, animals, and plants.

Pathfinders in oncology from the end of the 19th century to the first description of Ewing sarcoma.

During the period 1884 to 1922, the only option in cases of operable cancers was radical surgery, and only a minority of patients were cured. Sporadic attempts were made to treat inoperable cancer patients with bacterial toxins; however, with the discovery of x-ray and radium, the era of radiation treatment as an alternative to surgery began. The discovery of transmissible cancers and experimental growth of cancer cells offered new information and not only led to a better understanding of the cellular composition of cancers but also yielded important information that ultimately paved the way to chemotherapy. These efforts also advanced the understanding of the pathogenesis of tumors and induced new clinical and pathologic classifications and subspecializations. It is important to emphasize that many of the initiatives and discoveries made in Europe in the second half of the 19th century were first put into clinical practice in the United States during the first 2 decades of the 20th century, including the use of x-ray and radium for irradiation and as diagnostic tools. All things considered, the progress made between 1884 and 1922 came about through the hard work of many eminent individuals; however, there were 7 foresighted pathfinders (3 surgeons, 2 pathologists, 1 internist, and 1 physicist) who-despite their widely diverse backgrounds, personalities, and expertise-made remarkable contributions to oncology to an extent that is still felt today.

A history of the optic nerve and its diseases.

We will trace the history of ideas about optic nerve anatomy and function in the Western world from the ancient Greeks to the early 20th century and show how these influenced causal theories of optic nerve diseases. Greek and Roman humoral physiology needed a hollow optic nerve, the obstruction of which prevented the flow of visual spirit to and from the brain and resulted in blindness. Medieval physicians understood that the presence of a fixed dilated pupil indicated optic nerve obstruction, preventing the passage of visual spirit, and that cataract surgery in such cases would not restore sight. During the Renaissance, the organ of vision was transferred from the lens to the optic nerve, which was generally believed to be on the axis of the eye. The acuity of central vision (at the optic disc) was explained by the concentration of visual spirit where the optic nerve met the retina. The growth of anatomy and influence of mechanical philosophy from the 17th century led to visual spirit being replaced with the concept of nerve force, which later became associated with electricity travelling along nerve fibres. This coincided with discourse about the nature of the nervous system and a shift in orientation from understanding illness holistically in terms of an individual's humoral imbalance to the concept of organ-based diseases. Both the microscope and the ophthalmoscope allowed visualisation of the optic nerve, but problems of interpretation persisted until conceptual transformations in medical science were made.

[Historical Archives of Italian Nephrology. The history of instrumentation in nephrology. Part II: microscope and haemodialyzer]. / Archivi storici della Nefrologia Italiana. La storia della strumentazione in nefrologia Parte II: microscopio e dializzatore.

Medicine in the technological era acquired many of the characteristics that concurrently marked other fields. So, by adopting procedures based on information obtained with instruments and devices, medicine developed an approach to illness that transformed it into a special form of technology. The collective effect of instrumentation deserves consideration and offers the historian opportunities for interpreting the interaction between physician and his patients in other than scientific and technological terms. The very construction of instruments and devices depends on the Author's ideas assembled with the basic theories of the time. For instance, at the end of the nineteenth century, when medical instruments became essential, the bacterial origin of diseases revolutionised their construction and application. In this context, the invention and use of the microscope became an outstanding feature of the clinical approach by disclosing the cellular universe. The microscope had become crucial in locating some major causes of physical suffering and death in man, and was considered the pre-eminent diagnostic instrument in medicine. In the nephrological field, the microscope drew the physician into a universe of physical changes that were concealed to the naked eye. The microscope made possible the verification of some of Bright's brilliant ideas, something that helped physicians classify glomerulonephritis. Many nephrologists confessed "how few things are established in this subject (nephrology) and how many more difficulties are established, we have learned by experience with the microscope". The modesty of this claim is striking. In nephrology, as in other fields, the admission of ignorance proved to be the beginning of wisdom. This wisdom, based on the admission of ignorance and assembled through the commitment and ingenuity of the pioneers of the dialysis treatment, led to the treatment of end-stage renal disease and the guarantee of success. The technique of haemodialysis has been enriched by the new lexicon, which expresses different ways and ideas on the removal of the solute.

Coffee, microscopy, and the Lancet's Analytical Sanitary Commission.

Coffee was the most frequently analysed commodity in the Lancet's Analytical Sanitary Commission's reports on adulteration published between 1851 and 1854. Techniques of sample collection and microscopical investigation developed to analyse coffee were applied to other foods and drinks by Arthur Hill Hassall, and his findings were instrumental in establishing the first parliamentary select committee to investigate food purity in 1855. The committee's recommendations formed the basis of the 1860 Act to Prevent the Adulteration of Food and Drink. Hassall's research in applied microscopy has been interpreted by historians as marking a critical point in the campaign to secure tighter food controls and as an example of a public health debate being transformed by the precise measurements of a dispassionate scientist. This article questions the objectivity with which the ASC selected foodstuffs for analysis, the superiority of microscopy over techniques of chemical analysis, and the extent to which coffee was an adulterated commodity in the middle of the nineteenth century.