Bell–Magendie law

A dead, or rendered unconscious, animal would not produce the desired effect when posterior horn fibers, responsible for sensation and transfer of noxious signals, are stimulated.

[5] The third scientist, not credited in the name of the law, was the German physician and physiologist Johannes Peter Müller; he carried out neuroanatomical and physiological experiments on rabbits for quite some time and without success .

[7] Because the frog spinal cord is relatively simple and easy to remove, and the relationships between the nerve roots are more apparent, Müller could simplify his design, which also resulted in better reproducibility of the experiment.

Some science historians have better resolved to name it after both physicians, giving Bell the honorary first mention, although others have claimed that these are essentially two overlapping discoveries.

[8] The French were also proud with Magendie's many discoveries and the extension of human knowledge in the areas of pathology, physiology and pharmacology and stood firmly behind his claim on the matter.

Until his death in 1842, Bell would write against the methods of Magendie and in his letters and books he would disapprove of the "protracted cruelty of the dissection experiments"[9] .

The unmyelinated Group C nerve fibers that transmit pain and temperature from the pelvic viscera enter the spinal cord via ventral roots at L5-S3, thus violating the Bell–Magendie law.