October 7, 1920] 



NATURE 



197 



iliK- for each of the elements / of a set, can be 

 transformed into a Stieltjes integral. By making use 

 of th<- univocal correspondence, establishtKi by Peano, 

 bet\v<-<n the points interior to a rectangle and the 

 points on a segment of a line, functionals depending 

 upon two arbitrary functions can also be reduced to 

 simple Stieltjes integrals. 



The subject of the fifth lecture, which was given 



bv Prof. Niirlund, of Copenhagen, was "' Les ^qua- 



tfons aux differences finies." The lecturer gave a 



• ry complete discussion of the solutions of equations 



: the types 



In an interesting communication Prof. W. H. 

 ung proposed a new definition, which does not 

 olve an approximation by means of tetrahedra, for 

 • area of a curvetl surface. Th«' proposal is, first, 

 define the "area of a curve " as the square root of 

 I he sum of the squares of three integrals of the form 



\> 



^ydz-zdy. 



1 hen, the surface being determined by the equations 



*=/,{«,?»), y=f2{u,v), z=f,{u,v), 



iiposc the domain of u,v to be divided up into 

 • inentary rectangles in the u, v plane. The area of 

 surface is the limit of the sum of the areas of the 

 ; responding elementary curves. 



Prof. Weiss, the director of the Strasbourg Institute 



Physics, gave an account of the methods of sound- 



iging in use in the French .Army during the war. 



11' method normally employed was the same as that 



ii us<' in the British Army. A useful alternative was 



th"' method a courles bases, in which six or more 



microphones were placed in pair.s. The microphones 



-of each pwir were al>out a hundred metres apart, so 

 that the gun locus became a straight line (asymptote), 

 and at once gave the direction of the hostile gun. The 

 installation was very simple, and could be made in 

 an hour, while single sets of observations could be 

 reduced and reported in a minute. This method was 

 used, not for the accurate location of gun emplace- 

 ments, but for determining quickly which one of the 

 known hostile batteries was in action. Guns were 

 also successfully located by observations of the onde 

 de choque. The normals to this wave-surface deter- 

 mine a caustic which is nearly constant in form for 

 high-velocity shells. To locate' the gun emplacement, 

 a standard caustic drawn on tracing-paper was fitted 

 by trial to the normals determined by the instruments. 

 This method was used when atmospheric conditions 

 made the spherical wave imperceptible, and, although 

 less accurate, it gave very good results. A case was 

 quoted where 80 per cent, of the hostile emplace- 

 ments were correctly located solely by ondes de 

 choqtie. 



In the course of the congress receptions were held 

 by the Committee of Organisation, the Soci^t^ des 

 Amis de 1 'University de Strasbourg, the Mayor of 

 Strasbourg, and the Commissaire G^n^ral (M. 

 Ala petite). 



.At a concert organised by the Soci^t^ des Sciences 

 du Bas-Rhin, the delegates had the pleasure of hear- 

 ing 's Elsasxlied sung by the mixed choir of the 

 Concordia-.\rgentina Choral Society. The delegates 

 were entertained at the conclusion of the proceedings 

 at a banquet given by the Organising Committee. 



The invitation conveyed by Prof. Leonard Dickson 

 to hold the next congress in New York in 1924 was 

 accepted, and a further invitation was received to 

 hold the congress of 1028 in Belgium. H. B. H. . 



Disorders of Symbolic Thinking. 

 Discussion at the Congress of Philosophy at Oxford. 



CK^ HK.\I- subjects of direct scientific interest were 



•-^ discussed at th«' Congress of Philosophy held at 



"-'■•I on September 24-27. One of the greatest 



lice, because based on recent clinical and 



...::<.'ntal research, was the discussion introduced 



Dr. Henry Head in a paper <'ntitled "Disorders of 



nbolic Thinking due to Local Lesions of the 



lin." It raised the whole problem of the relation 



language to thought while concentrating attention 



the significance of certain definite obs<'rvations — 



•s of young men who had received cerebral injuries 



the war — in which the injur)- to the brain had 



• I ted tlv? power of articulation. 



>r. R. .Mourgue, of I'.Xsile de Villejuif, also con- 



uted a paper, and was announced to take part in 



discussion. He was unable to be present, how- 



I, and his place was taken bv Prof. Bergson. 



! )r. Head said that his general conclusion from the 



■5 he had stu<lied exp«'rimentally, where gross 



t ruction of brain-tissue had resulted in loss of 



■ ch, was that there always remairwd elements in 



■■'" which were not associated with words. 



s a discriminative movement capable of fin*- 



of adjustment, essentially on ifttelU^ctuat 



^m. Even in the gravest rases of aphasia 



, unt is evidently fully awnrc of his emotioni, 



' ran express ttv-m clearly in gesture and action. 



'••r tile iiidiienre of emotion he may eyen use 



which he is quite impotent to evoke 



■ rh can be disturbed, or even totally 



ultluiul reducing tfw patient's intellectual 



icity or of necessity producing grave intellectual 



• ■ t. .Ml the early work of investigation of aphasia 



y.c. 2658, VOL. 106] 



had been vitiated by the conception that speech was 

 a well-defined intellectual function, strictly localised 

 in some particular site in the brain. Attention was 

 concentrated, therefore, on correlating the extent of 

 anatomical destruction on this site with the character 

 of the disorder of speech. The fundamental error at 

 the root of all this work is its ignoring of the physio- 

 logical changes which intervene between the ana- 

 tomic-il lesion and the psychical states with which it 

 is associated. Destruction of the substance of the 

 brain disturbs the act of speech only because it inter- 

 feres with the physiological processes necessary for 

 its perfect execution. 



Dr. Head then described the nature of his exiieri- 

 ments and the means he had devised to discover the 

 physiological processes with which the particular in- 

 luries had interfered. In the older theories auditory 

 images were supposed to be responsible for 

 "memories" of words, and these were said to be 

 stored up in certain areas of the cortex. The hypo, 

 thesis is entirely unable to explain the phenomena of 

 aphasia. Patients who cannot name consecutively a 

 .series of objects in front of them can choose them 

 correctly wln'n th<' name is given «'ither orally orin 

 print. It is the name, not flie auditory linage, which 

 is lacking. The loss of the power to use words is 

 not due to a destruction of imag<-s. 



What, then. Dr. Head asked, are the functions which 

 are disturbed in aphasia? The true answ<-r had l>ecn 

 given so long ago as 1868 by Hughlings Jackson, 

 though its significance was not then sevn._ The chief 

 menial arlivitv disturbed by uniUiteral lesions of th« 

 brain was de<lnred to be the uw of words in proposi. 



