470 REPORTS ON THE STATE OF SCIENCE. 



III. Becompoiition Products. — Quantity of material insufficient to isolate satis- 

 factorily any products of decomposition in malodorous simdices, but merely empirical 

 tests do not indicate the presence of indol and skatol. In the extract of mature 

 spadix oiArnm erinititiii trimethylamine seems to be present, but the material was 

 too scanty for isolation. 



N.B. — Chloroform was found to be quite useless as an antiseptic where the 

 experiments extended over many days. 



Report of Miss Kemp on the Occurrence in certain Vegetable Tissues of a 

 Profagated Electrical Response to Stimulation. 



The literature dealing with the question of conduction of stimuli in 

 plants has been admirably reviewed by Fitting/ who also gives a complete 

 bibliography. 



Fitting is of opinion that propagation of an excitatory change in 

 response to a local stimulus occurs widely in plants and essentially in 

 cells with living contents, though whether such propagation takes place 

 by water movement on variations in the permeability of the cell mem- 

 branes and osmotic pressure, by changes of the gaseous pressure, or 

 by a more active metabolism of the individual cells remains problematic. 

 He divides the tissues through which transmission may occur into two 

 groups : (a) the living cells of the vascular bundles through which exci- 

 tation may be transmitted, even when the tissue is under the influence 

 of anaesthetic drugs or excessive changes of temperature ; (h) the ' ground- 

 tissue,' in which transmission is very dependent upon the condition of 

 the plant. He states that the propagated activity is associated with 

 galvanometric negativity, and gives as its speed in Biopltytum 10-20 mm. 

 per second. 



The following ob.servations have been carried out upon seedling plants 

 of mustard, pea, bean, and further upon adult petioles of maidenhair 

 fern. Electromotive variations have been taken as an index of the 

 excitatory changes occurring within the tissue, the latter being led off by 

 non-polarisable electrodes to a high -resistance galvanometer. 



By using a double galvanometer circuit, with one instrument under 

 observation in the laboratory and the other in a neighbouring photograJ)hic 

 room, it was possible to record the variations obtained at the same time 

 diagram matically and photographically. I have made upwards of 120 

 plotted observations and photographs, of which ele\ en have been selected 

 for representing the results in the present preliminary communication. 



With the exception of a few cases where the nature of the stimulus 

 was mechanical the thermo-electric method of stimulation has been used. 

 By this method, in which a platinum wire previously fixed in position 

 close to or actually again-st the tissue is heated by closure of an electric 

 current, the objection of shifting contacts liable to occur with any 

 mechanical form of stimulation is obviated. In each case the plant 

 under observation was placed upon non-polarisable leading-ofT electrodes 

 with an intrapolar distance of about \\ cm., and the stimulation was 

 applied at points successively nearer to these electrodes. Under these 

 conditions responses of an appai-ently diphasic chai-acter have been 

 obtained at distance* varying between 1-12 cm. from the point of 

 stimulation. 



The resulting curves appear to afford evidence of the propagation 



' Ergcbnisse der Physioloqie, vol. v. p. 165. 



