592 



NA TURE 



[October 8, 1908 



brtfciation in the magnesian limestone of Durham, showed 

 that the beds have been thrust against a horst, the flexible 

 beds have been deformed without being much broken, 

 while the harder, brittle limestone has been highly 

 brecciated. He estimates that the amount of lateral dis- 

 placement has been about loo yards, and by experimental 

 tests he indicates the magnitude of the thrust to have been 

 about 300 tons per square foot. 



1 he president, in opening a discussion on mountain 

 building, referred to recent investigations on mountain 

 structure, which revealed the fact that in the overlap of 

 recumbent folds the uppermost folds were of greater span 

 than those beneath, and this could not be explained on the 

 notion that horsts of the accepted type were responsible 

 for the features observed. He calculated that at the depth 

 at which the horsts were supposed to exist the rocks would 

 be in a viscous condition owing to radio-active heating 

 and incapable of transmitting a direct thrust. With rigid 

 rocks overlying a viscous. mass he showed that compressive 

 forces would cause the rocks to bulge upwards, and lying 

 folds would be produced. Sir .Archibald Geikie described 

 the two-fold types of mountains, one possessing the Alpine 

 structure and the other taking the form of plateaux up- 

 raised without disturbance except at their margins. He 

 could not accept the explanation offered by Suess for the 

 latter type, that the sea had fallen. He reminded the 

 audience that folding was not all of one age, and the forces 

 which have produced the Alps in the past may be acting 

 at the present day. 



Prof. Lapworth, in describing the principal mountain 

 ranges on the earth's surface, urged that in their distribu- 

 tion they follow the curves of harmonic motion. Those 

 existing beneath the ocean or as festoons of islands fall 

 in with the general scheme as illustrated by the law of 

 curves. All the islands of the world and all the moun- 

 tains are strung on a great circle which corresponds 

 with the line dividing the land and water hemispheres. 

 The northern and eastern hemispheres are above the node 

 of the great curve, while the southern and western hemi- 

 spheres are below the node. On the great master folds 

 there are smaller corrugations bearing the same relations 

 as the harmonics to the fundamental in a vibrating cord. 

 In this way the central depressions of continents can 

 be correlated with the submerged ridges in the ocean 

 depths. 



Prof. Sollas, in referring to the theory put forward by 

 the president, showed that piled-up folds would blanket the 

 deep-seated rocks, and a highly heated region beneath 

 mountain folds might account for the lower value of 

 gravity observed in the neighbourhood of mountain chains. 

 The approximation of remote areas brought about by fold- 

 ing involved the transference of viscous material from one 

 region to another. This would not onlv result in bulging 

 up, but in the lateral traverse of material. The thrusting 

 which built up the Alps and the Carpathians was felt in 

 the British Islands, and the cracks produced in the 

 splintered crust of Scotland and the north of England might 

 have afforded a passage for the underlying Tava, which 

 perhaps originated under the Alps. Given the deforma- 

 tional figure of the earth, the position of mountain chains 

 follows from it, since on Prof. Joly's theorv they will 

 arise where sedimentation has taken place, i.e. at the limit 

 of land and water. 



Prof. Cole suggested that the older opinion of Scrope 

 regarding uplift and sliding was receiving confirmation in 

 later days, and the festoon arrangement of islands and 

 mountain chains was the result of the frontal movements 

 of sliding masses. 



Palaeontology was represented in the section by papers 

 dealing mainly with the fossil Reptilia. Prof. H. G. Seeley 

 described a fossil reptile from the Upper Karroo of Cape 

 Colony which possessed a proboscis or trunk, and in a 

 second paper the dentitions of the Cynodontia and 

 Gomphodontia were contrasted. 



The occurrence of reptilian footprints in the Inferior 

 Oolite of Whitby was announced by Mr. H. Brodrick, and 

 in the Trias report Mr. H. C. Beasley described the tracks 

 of -nvcrtebratts found in association with footprints in the 

 Trii^sic rocks. 



Air. W. Whitaker, in describing a deep boring recently 

 "■^'ule on the Thames marshes at Cliffe, reported a fact 



NO. 2032, VOL. 78] 



which has an important bearing on the character of the 

 floor of older rocks underlying the Secondary rocks of 

 Kent. At 1030 feet below Ordnance Datum Silurian rocks 

 were penetrated. The practical bearing of the boring is 

 that it puts a northern limit to the Kent coalfield. 



?HYSlOLOG\ AT THE BRITISH 

 ASSOCIATION. 



T^HE large number of individual papers presented this 

 year made it necessary to hold afternoon .sessions 

 each day of the meeting, and even then it was difficult 

 to find room for all the papers. .Apart from the . presi- 

 dent's address, which has been published already 

 (October 1, p. 553), the various communications are de- 

 scribed herein, but owing to lack of space some of the 

 papers, which cannot be conveniently summarised, are 

 noted only by title. 



-After the presidential address, Prof. Sherrington, F.R.S., 

 read a paper on proprioceptive reflexes of the limb. In 

 a decerebrate animal the two hind legs are prepared so 

 that all the muscles, except the extensor of each knee, are 

 paralysed. Thus there is left on each side an afferent 

 and an efferent nerve supply from a single .muscle. The 

 limbs are supported so that the knee can be extended by 

 muscular contraction and flexed by gravity. Flexion at 

 the right knee causes extension of the left leg,' whilst 

 extension on the right causes flexion on the left ; that is, 

 stretching the extensors causes a reflex contraction of the 

 crossed extensors, and relaxation of the extensors produces 

 reflex inhibition of the crossed extensors. The tone of the 

 muscle depends on refle.x impulses from itself, and when 

 the extensor is passively stretched it does not return to its 

 original length, but, being inhibited, remains more flexed 

 than it had been ; conversely, relaxation of the extensors 

 leaves the limb in a more extended position. The final re- 

 port of the committee on the " metabolic balance sheet " of 

 the individual tissues was presented by Prof. Gotch, F.R.S. 

 The object of the committee, namely, the development of 

 sound and fruitful methods for investigating the meta- 

 bolism of individual tissues, having been accomplished, 

 it did not desire re-appointment. The report reviews the 

 work that has been done by the committee during the past 

 five years. The technique of various experimental pro- 

 cedures has been improved upon, and these improvements 

 are dealt with as follows : — gas analysis, anesthetics, pre- 

 vention of clotting, measurement of rate of flow, ■ and 

 analysis of gases of perfusion fluids. The organs employed 

 and a comparison of the results obtained are stated, and 

 the report concludes with a list of the papers so far pub- 

 lished as a result of the work of the committee. Sir 

 Lauder Brunton, F.R.S., whilst presenting the report of 

 the committee on the effect of climate on health and 

 disease, read a paper on influenza, showing that epidemics 

 of influenza are accompanied by an increased death-rate 

 from pulmonary diseases, and he compared these outbreaks 

 with various meteorological data. Dr. Grabham then gave 

 a paper on the physics of high altitudes in relation to 

 climate and health. From various measurements of 

 humidity, wind pressure, and electrical potential he sug- 

 gests that deficient electrical charge in the atmosphere is 

 one of the conditions in a relaxing climate. 



In the afternoon Prof. Swale Vincent presented the report 

 of the committee on ductless glands. The view that the 

 thyroid and parathyroids are intimately related is sup- 

 ported, and evidence is furnished that the suprarenal 

 gland constantly pours its secretion into the blood stream, 

 and thus regulates the blood pressure. Prof. Macalliim, 

 F.R.S., read two papers. In the first he recorded the 

 analysis of urine in polyuria produced by the ingestion 

 of large quantities of water. The total solids were so 

 reduced that freezing-point determinations showed a very 

 much reduced lowering. The percentage of chlorides de- 

 creased from the onset of polyuria, whilst that of potassium 

 did not diminish until later on ; thus at first the potassium 

 showed a marked rise relatively to the sodium ; at the 

 same time, he could not find any appreciable dilution of 

 the blood. These experiments are contrary to the view 

 that urine is merely filtered from the blood, but they 

 suggest that tliere is a selective action of the epithelial 

 cells. His second paper dealt with the distribution of 



