February 25, 1909] 



NA TURE 



507 



iiitiTcst in physiology, patliology, and therapeutics. The 

 hlood of Bengalis has been found by Captain Mackay to 

 contain a higher proportion of salts and a less proportion 

 of red blood corpuscles than the blood of Europeans. The 

 .luthor has found that the blood pressure in the natives 

 is lower than in Kuropeans, averaging about lOo milli- 

 metres of mercury. The pathological observations are that 

 in cholera the enormous secretion of f^uid into the bowel 

 drains away the fluid part of the blood. There is a very 

 definite relationship between the amount of fluid thus lost 

 from the blood and the severity and mortality of the 

 disease. Injections of normal saline solution (065 per 

 cent, of NaCl) into the veins have an almost miraculous 

 effect in relieving the symptoms and restoring the patient 

 10 apparent health. This improvement is, however, only 

 transient, and in the course of a few hours the symptoms 

 recur and the patients die. It occurred to the author that 

 if, instead of using a normal saline solution, he were to 

 inject a hypertonic solution of 135 per cent. NaC! into 

 the veins, there would be less likelihood of the diarrhoja 

 recurrinii, and the blood being again drained of its 

 fluid parts. The result of this treatment was extra- 

 ordinary. It has simply revolutionised the results, so that, 

 whereas formerly the recovery of a collapsed case was a 

 surprise, its non-recovery is now a disappointment. In 

 severe cases the proportion of chlorides in the blood falls 

 below the normal, notwithstanding the great concentration 

 of the blood from loss of water. He therefore sometimes 

 uses a saline solution of 1-65 per cent., but usualh' 1-35 per 

 cent, is sufficient. In bad cases the coagulability of the 

 blood Is very greatly reduced, so that the -author now 

 generally adds 3 gr. of calcium chloride to a pint of saline 

 solution. The development of ur;emia in the reaction stage 

 of cholera is associated with a comparatively low blood- 

 pressure ; measures to raise it, such as the hypodermic 

 adtninistration of adrenalin and digitalis, are indicated for 

 the prevention and treatment of this very serious com- 

 plication. — The British fresh-water phytoplankton, with 

 special reference to the desmid-plankton and the distribu- 

 tion of British desmids : \V. West and G. S. West. The 

 paper is in part a comprehensive summary of the known 

 facts concerning the phytoplankton of British fresh waters. 

 It has been possible to institute a close comparison between 

 the British phytoplankton and that of continental Europe, 

 proving that the British lakes are relatively richer in green 

 algiE and poorer in blue-green forms than the generality 

 of continental lakes. The large percentage of green species 

 in the British lakes is due, in most instances, to the domin- 

 ance of desmids. Certain diatoms also stand out con- 

 spicuously, especially some of the large species of the 

 Surirellacea-. -As the plankton investigations were not 

 commenced until the authors had acquired a very extensive 

 knowledge of the general British alga-flora, it has been a 

 comparatively easy matter to see wherein the phytoplankton 

 differs from the alga: of the littoral region and of the 

 bogs, &c. \n extended study of the distribution of British 

 desmids has shown that the rich dcsmid areas correspond 

 (1) to a considerable extent with the areas of greatest rain- 

 fall, and (2) to a much closer extent with the outcrops of 

 the older Palaeozoic and pre-Cambrian strata. The reallv 

 rich desmid-floras only occur in those western and north- 

 western districts in which the geological formations are 

 older than the Carboniferous, and these are likewise the 

 districts in which the British lakes are situated. There- 

 fore, the dominance of desmids in the phvtoplankton is 

 not so remarkable as might at first be supposed. Numerous 

 desmids are continually washed from the drainage-areas 

 into the limnetic region of the lakes, and some of them 

 have become leading constituents of the phvtoplankton, 

 either with or without change of morphological characters. 

 Many of them form a well-marked assemblage, the in- 

 dividual constituents of which are limited in their British 

 distribution to the western lake-areas, although most of 

 them occur in the lakes and bogs of .Scandinavia on pre- 

 cisely siiTiilar outcrops of old rocks. It is suggested that 

 perhaps the inost important factor in this relationship is a 

 chemical one, but, so far as observations have been made. 

 ordinary chemical analysis of the drainage-waters has 

 offered no clue to the solution of the problem. — The 

 selective permeabilitv of the coverings of the seeds of 

 Ifo'di'um viili;are : Prof. .Adrian J. Brown. It has been 

 N'O. 2052, VOL. 79] 



pointed out previously ('* Annals of Botany," 1907, vol. 

 xxi., p. 79) that the coverings of the seeds of barley act 

 as an exceptionally perfect semi-permeable membrane, 

 resisting the passage of acids, of alkalies, and of salts, but 

 not of iodine. Experiments are now described from which 

 it appears that not only strong electrolytes, but also dex- 

 trose, cane sugar, and other non-electrolytes are unable to 

 penetrate the membrane. On the other hand, mercuric 

 chloride and cyanide, but neither the nitrate nor sulphate, 

 cadmium iodicie, but not the chloride nor the sulphate, 

 aminonia, acetic acid and several of its homologues, alcohol 

 and ethylic acetate, are all capable of passing into the 

 corns. Glycollic and lactic acids also pass in, but far less 

 rapidly than acetic. The water-absorbing capacity of the 

 seeds when immersed in various solutions has been con- 

 trasted with that of the seeds when placed in water alone. 

 Far less water is absorbed from solutions of substances 

 which do not penetrate the seed covering than from those 

 containing substances which do. In the case of substances 

 which diffuse readily into the corn, such as ammonia and 

 ethvlic acetate, the rate at which water passes in is much 

 more rapid than from solutions of substances which do 

 not penetrate the covering, or from water alone. — The 

 origin of osmotic effects, ii., differential septa : Prof. H. E. 

 Armstrong. It is shown that the effects described by 

 Prof. Brown may be explained in terms of the theory of 

 the conditions of substances in solution recently communi- 

 cated to the society by the author. Substances such as 

 ammonia, acetic acid, &c., which exist in solution in a 

 slightlv bydrolatcd state, would pass the hydrolated surfaces 

 of the intramolecular passages in the colloid membrane, 

 whilst hydrolated solutes would be held back. The iii- 

 creased rapidity with which water enters in some cases is 

 trnceable to the effect which the diffusing substance has in 

 raising the osmotic stress in the water within the corn. 



February 4.— Sir Archibald Geikie, K.C.B., president, 

 in the chair. — The electricity of rain and its origin in 

 thunderstorms : Dr. G. C. Simpson. During 1907-8, an 

 investigation was undertaken at the Meteorological Office 

 of the Government of India, Simla, into the electrical 

 phenomena which accompany rain and thunderstorms, with 

 results which have led to the following theory. It_ is 

 e.N.ceedinglv probable that in all thunderstorms ascending 

 currents greater than 8 metres a second occur. Siich 

 currents are the source of large amounts of water, which 

 cannot fall through the ascending air. Hence, at the top 

 of the current, where the vertical velocity is reduced on 

 account of the lateral motion of the air, there will be an 

 accumulation of water. This water will be in the form 

 of drops, which are continually going through the process 

 of growing from small drops into drops large enough to be 

 broken. Every time a drop breaks, a separation of elec- 

 tricity takes place, the water receives a positive charge, 

 and the air a corresponding amount of negative ions. The 

 air carries away the negative ions, but leaves the positively 

 charged water ' behind. A given mass of water may be 

 broken up many times before it falls, and, in consequence, 

 may obtain a high positive charge. When this water finally 

 reaches the ground, it is recognised as positively charged 

 rain. The ions which travel along with the air are rapidly 

 absorbed by the cloud particles, and in time the cloud itself 

 may become highly charged with negative electricity. Now 

 within a highly electrified cloud there must be rapid coni- 

 bination of the' water drops, and from it considerable rain 

 will fall ; this rain will be negatively charged. A rough 

 quantitative analysis shows that the order of magnitude^ of 

 the electrical separation which accompanies the breaking 

 of a drop is sufficient to account for the electrical effects 

 observed in the most violent thunderstorms. All the results 

 of the observations of the electricity of rain described in 

 the paper are capable of explanation by the theory, which 

 also agrees well with the actual meteorological phenomena 

 observed during thunderstorms. — The effect of pressure 

 upon arc spectra, Xo. 3, silver, X 4000— \ 4600 : Dr. W. G. 

 Duffield. This paper is the third that the author has 

 presented to the Royal Society upon the effect of pressure 

 upon arc spectra. The behaviour of the iron, copper, and 

 silver arc spectra (region \X 400c>-46oo) has now been 

 described, the former under pressures up to 100 and the 

 last two up to 200 atmospheres. In course of time the 



