History of pathology

- The oldest civilized people (Chinese, Indians, Egyptians) were under the impression that disease occurred when demons or evil spirits were displeased with an individual. The medicine men were concerned with appeasing these evil spirits.

 -- During the Tigris-Euphrates era, veterinary medicine was first mentioned in recorded history. Veterinary medicine received a considerable degree of attention because of the importance of the horse to society. The "Laws of Hammurabi" (2100 B.C.) established rigid rules and regulations for veterinary practitioners, and these rules included the regulation of fees. In addition, the Hebrews, Babylonians, Greeks and Carthaginians made important contributions to the medical literature. However, the majority of this recorded history was destroyed by the Crusades and barbarians.

 -- The Egyptians began to influence medicine around 4000 B.C. These people were adept in certain phases of medicine, especially skull surgery. In addition,
embalming was an art employed by the Egyptians; many of these bodies (mummies) are still well preserved. There is no record of the Egyptians finding lesions or diseases during the embalming process.

 -- The Mosaic Doctrine (1500 B.C.) is the first recorded evidence of systematic meat inspection. These lays, as formulated by Moses and described in the books of Exodus and Leviticus, are similar to those we have today. Even though the Hebrews were advanced in food sanitation, they still accepted "divine displeasure" as the cause of disease.

 -- The Greek culture had a profound effect on the scientific approach to medicine. Greek physicians elucidated the principles of exact and careful clinical observations. However, they did not deal with the nature or the changes that occurred subsequent to disease.

1. HIPPOCRATES (460-375 B.C.)
AGreek physician, introduced the humoral theory of disease. He recognized four humors or fluids in the body:
 (1) blood which came from the heart;
 (2) phlegm which came from the brain;
 (3) yellow bile which came from the liver; and
 (4) black bile which came from the spleen.
Health was thought to be due to proper mixing of these four humors, while disease resulted from improper mixing. The humoral theory of disease was supported by three critical observations:
 (1) diseases were often characterized by increased discharge of fluid (perspiration, fever, vomition, diarrhea, catarrhal discharge, exudation, and transudation);
 (2) blood was the vital tissue and the individual died if exsanquinated;
 (3) the coagulation of blood was different in healthy and sick individuals.
Also, what was called phlegm is the same as fibrin. Those factors considered to be the effects of disease today were considered as causes by the humoral pathologists. The early humoral pathologists were not permitted to perform postmortem examinations on humans; thus, a confused concept of normal anatomy existed. Hippocrates is considered to be the Father of Medicine.

2. ARISTOTLE (384-323 B.C.)
A Greek philosopher, was the originator of modern anatomy and physiology. Also, he is considered to be the Father of Zoology. Aristotle dissected many animals, carried out experiments in physiology, and studied the growth and development of animal life (human autopsy examinations were forbidden during this period).

3. CLAUDIUS GALEN (129-201 A.D.)
A Greek physician practicing in Rome, was a follower of the beliefs of Hippocrates. Humoral pathology was brought to its height and most extreme development by Galen. Also, he wrote numerous medical documents and held despotic authority over European medicine for thirteen centuries after his death. Also, Galen is remembered for his views on meat inspection. He insisted that animals used for human food should be inspected prior to slaughter.

4. CORNELIUS CELSUS (30 B.C.-38 A.D.)
Was not a physician, but a man of leisure with a variety of interests. A great deal of the history of the early humoral pathologists was recorded in his work. A great number of the conditions recognized today are described in the work of Celsus. His writings described and discussed the cardinal signs of inflammation (redness, swelling, heat and pain).

5. RENATUS VEGETIUS (450-500 A.D.)
A Roman veterinarian, is credited with being the first author to write a textbook devoted exclusively to veterinary medicine. He was among the first to urge people to disregard Divine Displeasure as the cause of disease and to base their treatment and concepts of disease on a thorough knowledge of anatomy, surgery and medicine. Vegetius is considered to be the Father of Veterinary Medicine.
 -- During the middle ages, medicine entered into an era of nonproductivity and few contributions were made. However, the Renaissance brought forth profound advances in medicine and pathology. The works of Galen were questioned and new investigations were made. During this period, Divine Displeasure as the cause of disease began to gradually disappear.

6. WILLIAM HARVEY (1578-1657)
Described the blood vascular system and the circulation of blood in 1628. His works have had a far reaching effect on medicine and pathology.

7. ANTONY VAN LEEUWENHOEK (1632-1723)
Was the first to show that the microscope had practical importance in the study of tissues and other small objects (he is not credited with discovering the microscope).

8. JEAN FERNEL (1497-1558)
A Frenchman, was one of the first to describe diseases according to organs or parts of the body. he generally divided his diseases into those affecting parts above the
diaphragm, those involving parts below the diaphragm and external diseases. One of his books, entitled Pathologiae Libri, was the first medical work to be called a text of pathology.

9. GIOVANNI MORGAGNI (1682-1771)
An Italian, is recognized as one of the earliest pathologists and the originator of modern pathology. He was the first to correlate pathologic changes in the dead individual with clinical signs and symptoms shown by the individual during life.

10. MARIE-FRANCOIS XAVIER BICHAT (1771-1801)
A Frenchman, is credited with establishing the foundation for the study of histology, even though most of his work was done by physical and chemical methods (he did not possess a microscope). Bichat presented a new concept of anatomy and showed that the body was composed of twenty-one (21) tissues (vascular, osseous, muscular, cartilaginous, etc.). He is considered to be the Father of Histology.
 -- Modern veterinary medicine originated in France and the first modern veterinary school was established in Lyon, France on January 1, 1762.

11. JACQUES LABRESSIE DE SOLLEYSEL (1617-1680)
Published the first complete veterinary classic of this period, entitled Le Parfait Marechal. In this publication, Solleysel pointed out the adverse situation created by allowing the veterinary art to fall so completely into the hand of the Farrier. This book marks the beginning of the end of the horseshoer's regimen and control of veterinary medicine.

12. CLAUDE BOURGELAT (1712-1779)
A French veterinarian, was gifted in equine husbandry and wrote a book, entitled Elements of Hippiartry and the New Knowledge of Equine Medicine. He investigated and was successful in eradicating an outbreak of glanders in French Calvary horses. He was instrumental in establishing the first modern veterinary school in Lyon, France. In addition, Bourgelat established the veterinary school known as L-Ecole Veterinaire Nationale d'Alfort, located near Paris, France.

13. CARL ROKITANSKY (1804-1878)
A German, is considered as the supreme descriptive pathologist of all time. He firmly established the structural basis of disease as well as necropsy technique. However, he explained practically all diseases on the basis of blood anomalies.
 -- The field of pathology was completely reformed by cellular teachings which originated in Germany. The inspiration for this development came from Johannes
　
Mueller (1801-1858) who had many famous students (Schwann, Henle, Virchow and Schleiden).

14. RUDOLPH VIRCHOW (1821-1902)
Is known as the Father of Cellular Pathology.
He coined and explained many of the terms and concepts used today in pathology (amyloidosis, fatty degeneration, etc.). In addition, he started publication of "Virchow's Archives," a journal that has been in continuous publication since 1847. This is considered to be one of the most complete works of pathology in existence.

15. LOUIS PASTEUR
Frenchman, was one of the originators of the field of bacteriology. He demonstrated the importance of infectious organisms (bacterial) in disease. Pasteur studied human and animal diseases (pasteurellosis, anthrax, rabies, etc.) and showed that individuals could be successfully immunized by vaccines prepared from organisms.

16. ROBERT KOCH (1843-1910)
A German bacteriologist, established the Koch's Postulate, a procedure employed for proving a specific microorganism as the cause of a disease. He was the first to use artificial solid media in the attainment of pure cultures.

17. EDWIN KLEBS (1834-1913)
A student of Virchow, demonstrated the importance of bacteria in pathology.

18. JULIUS COHNHEIM (1839-1884)
A student of Virchow, is credited with being the originator of modern experimental pathology. He revealed the vascular alterations that are the basis of the inflammatory response.

19. WILLIAM H. WELCH (1850-1934)
A student of Cohnheim, is credited with bringing pathology to the United States. He was Professor of Pathology at John Hopkins University in Baltimore, Maryland.




REFERENCE: Principles of Veterinary Pathology; Runnels, Monlux and Monlux, 7th Edition, Chapter 2, pp. 6-21.