Surprising thought that diseases of plants should illustrate human pathology.

Will recommend A. B. Frank’s article in a German encyclopedia, on diseases of plants, to Francis Darwin.

Gives JP a good case of regeneration in plants – the radicle of the common bean. That plants have little power of regeneration is not difficult to understand by anyone who believes in Pangenesis, "if such a man exists … There is reason to think that my imaginary gemmules have small power of passing from cell to cell."

Refers to early experiments in which he tried to produce galls in plants by injecting poisons.