RECORD: Darwin, C. R. 1879.06.17. Phalaris with caustic. CUL-DAR209.8.122. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 7.2022. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volumes CUL-DAR209.7-8 contain notes on heliotropism (phototropism) for Darwin's book Movement in plants (1880).


[122]

June 17th. 1879

Phalaris with caustic on tips of Cotyledons before SW window in Black Box — Day moderately bright— Observed at 4° 40' Pm

A length of about 2 mm of tips was moistened & rubbed with Caustic

This represents 2 black dots to show in evening whether any growth

(1) 8° 12 am ⨀ ⨀— Black tip 2. mm— not grown — slightly heliotropic

(2) 8° 12 ⨀ ⨀ Black tip 3 mm— hardly grown— almost quite straight

(3) 8° 12 ⨀ ⨀ Black tip 4 mm— not grown— almost quite straight

(4) 8° 12 ⨀ ⨀ Black tip very small — not grown.— very slightly Heliotropic

(5) 8° 12' ⨀ ⨀ not grown Black tip 2 1/2 mm slightly Heliotropic.

(6) 8° 24' ⨀ ⨀ not grown — almost straight —Black tip 3 mm

(7) 8° 24' ⨀ ⨀ slightly Heliotropic

(8) 8° 24' ⨀ ⨀ Slightly Heliotropic

These experimentsa complete failure, for no growth cd be proved to have occurred in the 8 hrs in the lower portions of Cots— Moreover most of them were acted on by the light—

Say nothing about caustic on tips


This document has been accessed 245 times

Return to homepage

Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

File last updated 25 September, 2022