Thanks SHV for his letter [13455] in answer to his questions about the action of ammonium carbonate on the root cells of Euphorbia peplus. Suggests further observations.

Has read J. Sachs [Textbook of botany, English translation (1875)] and H. A. De Bary [Vergleichende Anatomie (1877)] on milk-tubes. He believes that tubes he has observed in germinating roots of Euphorbia myrsinites are modified milk tubes. Will send a paper on the subject to the Linnean Society.