426 Physiologie. 



ßy measuring the relative area occupied by the lumina of the 

 medullary ray cells in samples of coniferous wood, it was found 

 that they form not more than 3-5 per cent of the total area of cross 

 section and about Vis^h of the total area of tracheids in the cross 

 section of the stem. These cells are supposed to absorb water from 

 below, and excrete it from their upper part into the tracheids this 

 being facilitated by the circulation of the protoplasm within the 

 cells. The rate at which water would percolate downwards through 

 blocks of the same wood under the action only of its own weight 

 was then found. This leakage downwards was much greater than 

 could be overcome by the most rapid secretion of water upwards 

 which could be expected even from the maximum rates of proto- 

 plasmic Streaming observed in the living cells of the wood 

 parenchyma. 



With deciduous trees {Populiis alba, Acer pseiidoplatanns and 

 others) the discrepancy is even greater between the rate of water 

 flow needed to compensate for the downward flow, and that 

 obtained from the most favourable flgures according to Janse's 

 theory; the maximum rate of protoplasmic Streaming observed 

 being from -2 to -3 cms per min: and the average rate required to 

 account for the ascent of the sap being from ^76 to 5-82 cms per 

 second in the various types of wood examined. 



The authors suggest that the function of the medullary rays 

 is not to secrete water, but to conduct sugars from the bark to the 

 living cells of the wood where it may be stored as starch, respired 

 or secreted as sugar into the cavities of the neighbouring vessels 

 and tracheids. ^ E. M. Delf (Cambridge). 



Fräser, M. T.. Parallel Tests of Seeds bv Germination 

 and bv Electrical Response. (Ann. Bot. XXX. p. 181 — 189. 

 1916.) 



The author describes a series of preliminary experiments in 

 seed-testing. The living seed is found to give a definite electric 

 response, and the experiments were designed to shew how far the 

 response of soaked seeds corresponded with their subsequent power 

 of germination. The percentage of seeds which germinated in any 

 sample was termed their „germination value". 



The results shew that the same samples of grain, germinated 

 under approximately the same conditions give changes in the ger- 

 mination value and the electrical response which are quite con- 

 sistent. The electrical response of grains germinated under different 

 conditions varies in the same way as the germination value. There 

 is indication that the electrical response is sufficient to distinguish, 

 not only between living and dead seeds, but also between living 

 seeds of high and low vitality. If this is true, the raethod may be 

 of permanent value in seed-testing on a commercial scale. 



_2_ E. M. Delf. 



Haberlandt, C, Das pflanzenphysiologische Institut der 

 Universität Berlin. (Beitr. Allgem. Bot. I. p. I— XL 6 Fig. 

 1916.) 



Ein mit allen Errungenschaften der Neuzeit fast tiberreichlich 

 ausgestattetes Institut in Dahlem ist der Ersatz, den die Univer- 

 sität Berlin für das alte Botanische Institut Seh wendener's an 

 der Dorotheenstrasse erhalten hat. Das eigentliche Institutsgebäude 



