312 REPORT— 1903. 



latter is abundant in a cell. The quantity of potassium required by 

 protoplasm is very small, as shown by the feebleness of the reaction 

 obtained in the growing points of vegetable organisms. In old as com- 

 pared with young cells the quantity is great, but the excess is stored away 

 in the inert form, and is apparently due to the protoplasm precipitating it 

 from the water constantly diffusing into the cell. This may explain the 

 high proportion of potassium found in the cells of vegetable forms, and it 

 seems to indicate that more is present than is required. Further, the 

 varying amounts in different vegetable forms may be accounted for as 

 caused by variation in the flow of the sap, in the transpiration currents, 

 and perhaps also in the dissolving powers of the secretions of the root- 

 hairs. 



When the potassium salt is stored away in the inert form it is, unlike 

 the inorganic iron, still subject to solution and redistribution by the proto- 

 plasm, as is illustrated in the case of the spores of equisetum, the potas- 

 sium of which is in by far the greater part transferred on division to that 

 daughter cell which gives origin to the primary rhizoid. A similar control 

 over the precipitated potassium is found in the formation of the zygospores 

 of spirogyra. 



3. In the cytoplasm of the animal cell the potassium as a rule is much 

 less abundant, and when this element predominates in the medium from 

 which protophyta derive their abundance of potassium the accompanying 

 animal forms contain only traces of it (vorticella), and then chiefly in the 

 form of small localised precipitates. The unicellular animal organism 

 appears to be capable of rejecting the potassium even when it comes in the 

 food masses. On the other hand the cytoplasm of the epithelial cells in 

 the intestine and the excretory organs of vertebrates and invertebrates is 

 deeply impregnated with potassium salts which appear to be in the process 

 of excretion. 



4 In striated muscle fibre the potassium is limited wholly to the 

 doubly refractive material in the dim band (frog). This is significant 

 seeing that the potassium greatly exceeds the sodium in voluntary muscle 

 fibre, the proportion in frog's muscle being 557 : 100. The element is 

 found also in the doubly refractive material of the fibres in the wing 

 muscles of insects and in the muscles of the lobster. Here there can be 

 no reason for doubting the natui-e of the reaction, since creatin does not 

 occur in the tissues of invertebrates. 



It is proposed to continue the investigation of the disti'ibution of 

 potassium in the cell, and to make an extensive examination for this 

 purpose of a large number of animal and vegetable forms. 



Terrestrial Surface Wanes. — Report of the Committee, consisting of 

 Dr. J. Scott Keltie (Ghairma/n), Dr. Vaughan Cornish (Secre- 

 tary), Colonel F. Bailey, Mr. E. A. Floyer, Professor J. Milne, 

 and Mr. W. H. Wheeler. (Drawn up by Dr. Vaughan Cornish.) 



[Plate X.] 



Variability of the Severn Bore. 



This phenomenon is subject to apparently capricious variations in addi- 

 tion to that which depends upon the varying amplitude of the tide. 

 Visiting Newnham-on-Severn on the occasion of one of the highest tides 



