jan 1, 1862 - Blood Evidence: The Guaiac test for blood is developed

Description:

The guaiac resin test, using a plant-based compound that produces a blue color in the presence of blood (due to the peroxidase-like activity of hemoglobin), becomes one of the earliest presumptive tests for blood. It can detect blood in trace quantities and becomes widely used in forensic investigation throughout the late 19th and early 20th centuries.

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