Which theory upturned the humoral theory of illness in the modern era?

The question asks which theory "upturned" (overturned or replaced) the humoral theory of illness in the modern era.

• The humoral theory was an ancient medical concept that proposed that illness was caused by an imbalance of four bodily fluids (humors).
• In the modern era, medical understanding shifted significantly with the development of new theories based on scientific observation.

Let's evaluate the options:

• a. Disease automation: This is not a recognized medical theory that replaced the humoral theory.
• b. Behavioural analysis: This is a field of psychology and does not describe a theory of illness that replaced the humoral theory.
• c. Cellular Pathology: Developed primarily by Rudolf Virchow in the 19th century, cellular pathology established that diseases originate at the cellular level. This theory revolutionized medicine by shifting the focus from imbalances of humors to specific changes and dysfunctions within cells and tissues, thereby fundamentally upturning the humoral theory.
• d. Functional theory: This term is too general and does not refer to a specific medical theory that replaced the humoral theory.

Therefore, Cellular Pathology is the theory that replaced the humoral theory of illness.

The correct option is:
c. Cellular Pathology