Growth and tropic movements of plants / by Sir Jagadis Chunder Bose.

  • Bose, Jagadis Chandra, 1858-1937.
Date:
1929
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Licence: In copyright

Credit: Growth and tropic movements of plants / by Sir Jagadis Chunder Bose. Source: Wellcome Collection.

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    concordant testimony could leave no doubt as to the authenticity of the newly discovered facts. Advanced in- vestigation necessarily depends on the use of specially devised instrumental appliances and on the proper understanding of the technique of new methods, which can only be acquired after sufficient training. The perfect reliability of my highly sensitive instruments has been repeatedly verified at various scientific centres both in the West and in the East. The technical knowledge of the new methods can be gained after a certain amount of practice. Professor Hans Molisch, lately Director of the Plant-Physiological Institute, Vienna University, during his recent visit to my Institute, was able to repeat, with invariable success, many of the experi- ments described in this volume. His account of some of these will be found in Nature of August 4, 1928, and of April 13, 1929. It must be confessed that I was completely baffled, at the beginning of my researches, by many results which were as astonishing as they were unexpected. It was long per- sistence and careful comparison of numerous records that ultimately led to the elucidation of all anomalies. Attention had hitherto been centred on the end-effects, which, taken alone, are misleading. Examination of continuous records under prolonged stimulation showed clearly the gradual transformation of what may be regarded as the normal reaction to its very opposite. With such basic facts to work upon, it was afterwards possible to discover the causes of transformation. I may here briefly refer to a few of the more important results. For instance, the excitation of plants by radiation had come to be regarded as more or less confined within the narrow range of the visible spectrum. Experiments on the effects of wireless waves and of a high-frequency alter- nating field of electric force prove, on the contrary, that the sensitivity of plants to the ethereal spectrum extends far beyond the infra-red region. An unexpected factor in the modification of normal