December 5, 1901] 



NA TURE 



113 



weak. Other lines have made (heir appearance, the strongest 

 of which are 3868 and 3970, 4364 and 4720. The first is an 

 unknown line strong in the spectra of planetary nebulae, while 

 the other three are of unknown origin. It is suggested that the 

 second line (3970A) is not the line of hydrogen at lie, as the 

 other hydrogen lines in the spectrum are so weak. There is, 

 further, a new line in the ultra-violet at wave-length 342 (about), 

 which Gothard has independently recorded. It is interesting to 

 note that the new gas lines show a structure somewhat similar 

 to that of the hydrogen lines in earlier photographs. The 

 enhanced lines of iron, magnesium, &c. , which were such a 

 conspicuous feature of the first photographs, have entirely dis- 

 appeared, and the probability is that the bright lines now, other 

 than hydrogen and helium, belong to gases the terrestrial 

 equivalents of which have not been found. 



V'ariation of Latitude.— Prof. S. C. Chandler has made 

 an exhaustive examination of the old records obtained with the 

 reflex zenith tube at Greenwich from 1852-82, which were 

 abandoned as being affected with undiscoverable sources of 

 instrumental error, and finds that for the periods providing con- 

 tinuous measures throughout the year they yield most valuable 

 data for the determination of latitude variation, and that this 

 anomaly, unknown at the time, was most probably the cause of 

 the want of agreement among the observations. The two 

 periods yielding continuous values were 1857-63 and 1864-70 

 (Astronomical Journal, vol. xxii., No. 511.) 



Determination of the Elevation of Meteors. — 

 During the rather brilliant display of Perseids in August last a 

 series of successful experiments was made by the observers at 

 Juvisy Observatory to determine the heights of as many meteors 

 as possible. Two stations, Juvisy and Croix-de-Berny (.\ntony), 

 were chosen at a distance of 9-200 km. The number of meteorT 

 registered at both stations was 21, of which 8 fulfilled all 

 the necessary conditions for tlie determination, and a table is 

 given showing their calculated heights of appearance and dis- 

 appearance, and also the resulting length of trajectory. The 

 lowest record is 15 km. and the highest 1 19 km. {Bulletin de la 

 Soii^ti Astronomique de France, November 1901.) .' 



Meridian Observations at Harvard College Obser- 

 vatory. — In a separately published portion of vol. xli. of the 

 Annals of Harvard College Observatory (No. 7 , pp. 189-211) 

 Mr. A. Searle gives an account of a series of special investiga- 

 tions which have been in progress with the hope of eliminating 

 several systematic errors in the transit observations. It was 

 thought that these might be due to the employment of ruled 

 glass plates instead of spider threads, and for a time the latter 

 have been substituted for trial. The result showed that the 

 change produced no important difference in the discrepancies 

 referred to. Personal equation with respect to magnitude was 

 noticeable in both right ascension and declination when the 

 transits were taken over inclined lines, as was the case with the 

 ruled glass plates formerly used. 



Length of the Terrestrial Day.— Mr. R. S. Wood- 

 ward has been investigating the extent to which the secular 

 cooling of the earth and the fall of meteoric dust may affect 

 the length of the terrestrial day. Attention is first drawn to 

 the conclusion of Laplace that the day has not changed 

 appreciably owing to secular cooling during the past 2000 

 years, but this was on the assumption that the earth is in the 

 last stages of cooling. This the present author thinks an 

 unnecessary and doubtful restriction, and proceeds, using the 

 other conditions identical with those of Laplace, to develop a 

 method of determining the effect on the length of day of 

 the cubical contraction of the earth during any portion of, or 

 during the entire history of, the process of secular cooling. 



It is suggested that, contrary to the views of Laplace, 

 Fourier and Poisson, the dissipation of 'the internal heat of 

 the earth is not controlled by the atmosphere and oceans, but 

 escapes as if they did not exist. 



The main conclusion is that in the entire history of secular 

 cooling of the earth the day may be shortened from this 

 cause by as much as 6 per cent, of its original length. With 

 respect to a definite time variation, it is concluded that the 

 length of the day will not change, or has not changed, as the 

 case may be, by so much as half a second in the first ten 

 million years after the initial epoch. 



The coricluding portion of the paper deals with the effect of 

 accumulations of meteoric dust. The distribution is assumed 

 as uniform over the surface. Taking Newton's estimate of the 



number of meteorites falling daily, it is calculated that at least 

 a million million years would elapse before a change of a 

 quarter of a second would be produced. The effect of secular 

 cooling is thus considerably more than that of meteoric 

 accumulations. (Astronomical lournal, vol. xxi, No. 502). 



PHYSIOLOGY AT THE BRITISH 



ASSOCIATION. 



yi 



NO. 1675, VOL. 65] 



HE Section of Physiology was presided over by Prof. 

 McKendrick, F. R.S., and the place of meeting was Prof. 

 McKendrick's laboratory at the University. Despite the near 

 approach of the date of the fifth triennial International meeting 

 of Physiologists held at Turin in September, the Section was well 

 attended by working physiologists, and the audiences were often 

 large. Profs. Schafer and Sherrington were vice-presidents, and 

 amongst others contributing to the meetings were Sir Michael 

 Foster, Sir John Sanderson, Dr. Theodore Beer, Dr. Brodie, 

 Miss F. Buchanan, Dr. Burch, Prof. Gotch, Dr. \. A. Gray, 

 Dr. Edridge Green, Prof. Marcus Hartog, Dr. Kennedy, Dr. 

 Myers, Dr. Noel Paton, Prof. Waymouth Reid, Dr. W. H. R. 

 Rivers, Prof. W. H. Thompson, and Dr. J. A. Wanklyn. 



The proceedings of the Section commenced with the presi- 

 dent's address. Prof. McKendrick took for his theme the 

 relation of physical and chemical structure as understood at 

 present to our conception of the structure of living matter. The 

 president commenced by pointing to the progress which had 

 been made by physiology in the quarter of a century that had 

 elapsed since the previous meeting at Glasgow. Physiology in 

 its progress had proven itself a living and logical inductive 

 science grappling successfully with its problems by help of the 

 same laws that physics and chemistry apply to non-living matter 

 and its phenomena. In this respect it contrasted strikingly 

 with subjects, e.g. human anatomy, which had been closely 

 associated with it formerly in educational curricula. 



Physiology had in the last quarter of the century proved 

 fruitful of discovery to an astonishing extent. Many of its dis- 

 coveries were of high practical value to medicine as well as of 

 theoretical value. It had struck deep into the soil, acquiring 

 many new data of extreme accuracy and obtaining much pro- 

 founder insight in the concatenations of the machinery of life. 

 The phenomena of muscular contraction — that prime event in 

 biodynamics, — the process of secretion by gland cells, the 

 mutual synergy of organs as illustrated by internal secretion, 

 the functional architecture of the nervous system, the mechanics 

 of rejuvenescence of protoplasm by sexual recombination (fer- 

 tilisation), all these branches of the physiological tree of know- 

 ledge had, under the cultivation of the last five and twenty 

 years, grown vastly in extent and yielded blossom and invalu- 

 able fruit. Facts more accurate and theories more profound 

 had drawn their science closer to the elder sister sciences of 

 more exact measurement and at the same time had created, 

 it must be admitted, a gap between it and subjects with which 

 it had formerly been usually associated in teaching. It had 

 widened the educational field and educational worth of physio- 

 logy, releasing it from former restriction to narrower technical 

 applications. Save in mathematics, knowledge cannot be ab- 

 solute in any domain of natural science. Physiology shared with 

 the sister sciences their birthright of problems that were, to speak 

 in paradox, the more insoluble the further one progressed toward 

 their solution. 



The animal body— the human body — was a machine of high 

 complexity, constituted of many interrelated parts, called organs, 

 the ■' simple" tissues and the " compound " tissues. A number 

 of its phenomena had indubitably received their lasting explana- 

 tion ; but the difficulty of examining the machinery of living 

 matter while still in living action was extreme. The first step 

 of the chemist's analysis was to kill the substance ; yet his goal 

 was analysis of matter still alive. A number of thoughtful 

 physiologists had returned in recent years to study of the unit 

 of physiological structure, the cell. F'or the study of the 

 phenomena of life an object more suitable than the undiffer- 

 entiated single independently living cell was in many cases a 

 simple tissue composed of numbers of such cells associated and 

 highly differentiated, but all differentiated in the same way one 

 as another. Hence the tendency of the modern physiologist 

 to examine the powers and reactions of the simple tissues 

 rather than of unicellular organisms such as amreba. It 

 must be admitted, however, that in spite of all their labour in 

 many respects their knowledge had not yet reached far. For 



