June 27, 1907] 



NA rURE 



213 



columns cannot be maintained for any length of time in 

 the vessels of tall trees without the aid of the living cells 

 of the wood. 



The energy required to pump water upwards in the 

 tallest trees represents only a small fraction of that pro- 

 duced by the daily photosynthetic assimilation, and it is 

 the feeble character and diffusencss of the pumping action 

 which render it so difficult to demonstrate practically. 



Kxpcriments on the suction and exudation of trees at 

 dilTerent levels and upon the influence of the entry of air 

 and water under pressure showed that no continuous 

 suspended water columns, or high internal tensions, existed 

 in the conducting elements of the trees experimented on 

 (maple and poplar) during active transpiration, or, indeed, 

 at any period of the year. 



The same was shown by direct measurements of the 

 pressure in intact vessels of Wistaria during active tran- 

 spiration. This fact, coupled with the high total resist- 

 ance to flow, shows that this resistance is overcome locally 

 from point to point, and not by any enormous tension from 

 above or pressure from below, neither of which exists, nor 

 could be maintained to a sufficient extent to carry on the 

 elevation of water in a tall tree. A high tension from 

 above leads to rapid blocking with air ; a high pressure 

 from below leads to great loss by lateral exudation from 

 the vessels. 



The surface adsorption of dissolved solids in the vessels 

 plays a very important part in their function as trans- 

 locatory channels, causing a delay in the ascent of dis- 

 solved solids, such as sugar and salts, and an accumulation 

 of them along the outer walls of the vessels. The latter 

 facilitates their outward diffusion, but at the same time 

 renders the transference of small quantities of material 

 between widely removed organs difficult or impossible. 



The tallest trees in Australia do not appreciably exceed 

 ^00 feet in height, so that the values previously given for 

 the maximal total resistance to the upward flow of sap 

 in actively transpiring trees must be reduced to between 

 thirty and fifty atmospheres. 



May 30. — " Report of Private Expedition to Philippe- 

 ville, Algeria, to View the Total Eclipse of the Sun on 

 .\ugust 30, 1905." l^y Dr. T. C. Portef and \V. P. 

 Colfox. 



The two observers camped out on a hill near the village 

 of St. Charles, in lat. 36° 45' 38"7 N. and long. 

 *^° 5'' .W"''. 'in'^ ^Qo fs*"' above sea-level. The line of 

 central eclipse passed directly over their station. They 

 had magnificent weather on the day of the eclipse, and 

 were able to carry out almost all the observations contem- 

 plated, both visual and photographic. Two simultaneous 

 photographs were taken of the corona through two large 

 Nicol prisms, the axes of which made angles of 45° with 

 the horizon, and were at right angles to each other. The 

 negatives, and also the reproductions given in the paper, 

 vhow very strikingly the radial polarisation of the outer 

 corona : one of the streamers, for example, can be traced 

 with certainty from within 2' 7" to 2-2 diameters away 

 from the mnon"s limb on one of these photos., whilst 

 no part of it can be so traced on the other. There is 

 unmistakable evidence in both photos, that the coronal 

 development as a whole was more considerable on the 

 N.E. limb of the sun, i.e. on the side where the great 

 prominence was visible. The telescopic examination of the 

 details of the inner corona on the N.E. limb proved ex- 

 ceptionally interesting, a superb radial " pillared " struc- 

 ture being seen, cut by the streamers at various angles, 

 and limited externally by a very thin shell concentric with 

 the sun, suggesting partial condensation and a possible 

 differentiation of the " reversing layer " into concentric 

 shells of vapours of varying condensability. Jets were also 

 observed on the S.E. limb of a different colour from that 

 of the prominences visible, their narrow stems being white, 

 but passing into " rounded, soft-looking summits of the 

 bluish-pink of the cyanogen flame." \ photograph of 

 ihe " coronium ring," taken with a specially prepared 

 screen, revealed obvious jets, forty being easily counted 

 on the enlarged negative, and it is shown in the paper 

 that these must be attributed either to " coronium " itself 

 or to some unknown element the radiation from which was 

 capable of penetrating the screen used. 



NO. 1965, VOL. 76] 



The so-called " shadow bands " were very well seen, 

 both before and after totality, and are fully discussed in 

 the paper. They were waved, and the waves seemed to 

 have a inotion of their own along the lines of shadow, 

 which makes it almost certain that the true direction of 

 travel of each band considered as a whole was not at right 

 angles to its length, though at first sight the bands seemed 

 to be so travelling. It was proved that the directions of 

 the lengths of the bands coincided within the errors of 

 experiment with the trace on the horizontal sheet on which 

 they were observed of the plane passing through the cusps 

 of the solar crescent and the sheet ; the frequently observed 

 rotation of their direction during the progress of an eclipse 

 is accounted for. A full meteorological record was kept 

 for a few days, both before and after the eclipse day, and 

 the information gained is all exhibited on one chart, from 

 which the reduced barometric height, the humidity, solar 

 radiation, temperature of the air, direction and force of the 

 wind, and amount and distribution of cloud, as well as its 

 kind, can be read off for any hour of the day, and during 

 the eclipse for every ten minutes. The total length of the 

 certainly disturbed-barometer district at any one moment 

 was some 5000 odd miles, the part of it preceding the 

 umbra being some 200 miles shorter than that following 

 it, and the barometric maximum seems to have travelled 

 about 500 miles behind the centre of the umbra, and to 

 have covered a region about the same number of miles 

 in length, measured along the line of central totality. The 

 eclipse wind is discussed, and seems to have been due to 

 the inrush of air from all sides towards the centre of the 

 shadow, the effect of this influx being superposed, at the 

 station, on the northerly sea breeze. The direction of 

 motion of the shadow bands had certainly a large northerly 

 component, and thus their motion was also towards the 

 line of central eclipse, thus following the general direction 

 of the wind. A careful estimate of the height of the re- 

 flecting layers of matter in the earth's atmosphere, made 

 by measuring the altitude of the orange glow seen near 

 the horizon during central totality, gave six miles, a result 

 coming very near the inferior limit given by many hundreds 

 of observations in different latitudes by one of the observers. 

 The stars seen during totality were Venus, Mercury, 

 Regulus, Spica. Arcturus, and Procyon. 



" An Experimental Inquiry into the Nature of the Sub- 

 stances in Serum which influence Phagocytosis." (Second 

 communication.) By George Dean. Communicated by 

 Dr. C. J. Martin, F.R.S. 



(i) Dilution of fresh unheated serum is not accompanied, 

 so far as the higher concentrations are concerned, by a fall 

 in the sensitising power for certain organisms (staphylo- 

 coccus, tubercle bacillus). The diminution in this was 

 found, as a rule, to begin at the quarter concentration. 



(2) So far as the present e.xperiments go, the points 

 corresponding to the i/4th, i/'Sth, i/i6th, and i/32nd 

 dilutions of normal human serum lie on a parabola the 

 equation of which is y= = 4X, i.e. for these dilutions the 

 phagocytosis is proportional to the .square root of the 

 serum concentration. 



(3) The phagocytic index obtained by mixing appropriate 

 dilutions of a heated immune serum with a normal fresh 

 serum is greater than results from the tw^o substances 

 acting separately. 



(4) In the case of certain normal sera (guinea-pig and 

 rabbit) previously investigated for amboceptor and comple- 

 ment in relation to the extra-corpuscular bacteriolysis of 

 the typhoid bacillus (Wechsberg), an exact parallelisin can 

 be demonstrated to exist between that function and opsonis- 

 ation. The normal ainboceptor can be complemented by 

 fresh serum in regard to both functions, 



(5) An " anti-complement " serum, when mixed with a 

 fresh normal serum alone or in a mixture containing heated 

 iinmune serum, throws out of action the thermolabile 

 substance, whereas it does not appear to influence the 

 thermostable substance. 



" The Correlation of the Ovarian and Uterine Func- 

 tions." By E. S. Carmichael and Dr. F. H. .\. 

 Marshall. Communicated bv Prof. E. A. Schafer, 

 F.R.S. 



(i) The removal of the ovaries in young animals (rodents) 

 prevents the development of the uterus and Fallopian tubes. 



