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ELECTRICAL PHENOMENA AND METABOLISM OF ARUM SPADICES. 465 



similar to diphasic effects on nerve and muscle. The only difference is 

 one of speed, viz. — 



M. 0-300 in Dionem. 



3'000 in ordinary muscle. 

 0'150 in cardiac muscle. 

 30000 in nerve. 



The transmission in Biophytum was studied and described in 1890 

 and in 1898 by Haberlandt in the Buitenzorg Laboratory (Ueber die Reiz- 

 bewegung und die Reizfortpflanzung bei Biojihytum sensitivum, ' Annales 

 du jardin botanique de Buitenzorg,' Suppl. ii., 1898, p. 33). Haberland 

 gave as the speed of transmission at its quickest 2-5 to 3 mm. per 

 second, as compared with 8 mm. per second in Mimosa. 



In a more recent publication (' Sinnesorgane im Pflanzenreich,' Leipzig, 

 1901), Haberlandt (p. 152) compares transmission in plants with the cell- 

 to cell transmission obtaining in cardiac muscle, and rejects the assump- 

 tion of special fibrillar paths of excitation in vegetable tissues. 



Bose ('Comparative Electro -physiology,' 1907, chap, xxx.) deals with 

 the subject of transmission in plants at considerable length. He gives, 

 e.g., as having been determined by himself by the electromotive method, 

 the following values : Mimosa petiole, 14 mm. per second ; isolated nerve 

 of fern, 50 mm. per second ; and is of opinion (p. 453) that, since the 

 conduction of ' excitation takes place by the transmission of protoplasmic 

 changes, it is evident that it must occur most easily along those paths in 

 which there is greatest protoplasmic continuity. It is clear that certain 

 elements in the fibro-vascular bundles will furnish the best conducting 

 medium.' 



But the data upon which the author rests his opinion do not bear 

 examination ; in fact, the chapter on the matter contains no data unless 

 the diagram on p. 454 of an experimental arrangement for comparing 

 transverse and longitudinal conductivities be regarded as a datum. 

 Moreover, as stated above, the discovery of vegetal nerves similar to 

 animal nerves is altogether illusory. 



Report of Miss Sanders' Work done on Metabolism q/"Arum spadices, 



1908 (January to July). 



The subject proper of the present inquiry — viz., the further elucidation 

 of the changes going on in Arum sjmdices during inflorescence — has been 

 but little advanced this year owing to the difficulty of bringing- plants 

 during their first season to a pi'oper state of inflorescence. 



The points which we held before us particularly were : — 



1. The normal electrical conditions of variously active phases, 



2. The chemical products of the proteolytic activity which had been 

 shown to exist. 



'2b. The relation between the secretion of oxidases and amylases. 



3. The behaviour of the active parts under traumatic conditions and 

 after stimulation. 



These points we desire fo keep in view for a possible larger supply of 

 flowers in the future. 



From the few plants (about fifty) that flowered properly this season 

 it was, however, found possible to extend observations on (a) the enzyme 

 activity ; (b) the nuclear changes of cells governing this intense meta- 

 bolism. Of these I hope to give figures in September. 



1908. H H 



