Asks SHV about nature of granular matter formed in root cells of Euphorbia peplus which have been placed in solution of ammonium carbonate.

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.

More observations of the radicles of germinating seeds of Euphorbia peplus for appearance of milk-tubes.

Comments on J. v. Wiesner’s and W. F. P. Pfeffer’s views and criticism of his experiments.

Rows of cells with granular matter following treatment with carbonate of ammonia also found in white and young rootlets of common zonal Pelargonium. Differs slightly from Euphorbia in that 2, 3, 4, or 5 rows often adjoin. CD wrong in supposing that these rows of cells were connected with lacticiferous ducts ("milk-tubes"). Root hairs arise exclusively from rows of cells without brownish granular matter. It appears that certain rows of cells with hairs are absorbent and store matter of some kind. This is a new view of the structure and function of rootlets. Francis Darwin will soon set up the salt solution to make the experiment SHV recommends.

Describes experiment in which Euphorbia and Drosophyllum roots were exposed to ammonium carbonate solution. Asks SHV’s opinion.

CD will put together his notes on the action of carbonate of ammonia on roots in a few days. Asks SHV to send any information he may have, but not to answer if he has none. [See 13666.]