2(3 Presents. [Nov. 15, 



higher level and remains at this level during the period of excitation, and 

 then returns. The direction of the movement indicates that the longitu- 

 dinal surface has become negative to the cross-section. This corresponds 

 to the persistent (tonic) muscular effect which is characteristic of the first 

 stage of an epileptic fit. Proceeding from right to left, the cessation of the 

 excitation is seen to be followed by a rhythmical series of excursions, which 

 at first follow one another in rapid succession, but are small in extent, and 

 which subsequently occur at longer intervals, but are much more pro- 

 nounced in character, until at d they suddenly cease. This corresponds to 

 the clonic stage of the epileptic convulsion. 



Fia. 5. The photograph shows the rhythmical (clonic) effect only. The 

 recording surface was made to travel more rapidly past the slit, a marked 

 rhythmical change having been first evoked by excitation of the cortex. 

 The plate was not allowed to commence its passage past the slit until six 

 seconds after the excitation had ceased. The rhythm is thus seen to great 

 advantage. As before, the upward movement of the mercury, as indicated 

 by the elevations of the more darkly toned parts, are due to electromotive 

 changes in the cord such that the longitudinal surface of the cord becomes 

 negative to the transverse section. 



FIG. 6. Photograph showing the effect obtained when, with the spinal cord con- 

 nected as in the preceding with the electrometer, the cortex cerebri is 

 removed and the corona radiata excited by faradisation. The excitation 

 commenced at a and ceased at c. It is accompanied by an upward 

 persistent movement of the mercury, shown in the photograph as an 

 alteration of level, and corresponding in character to the (tonic) effect 

 produced during the excitation of the cortex. On the cessation of the 

 stimulus the effect subsides and is not followed by any rhythmical effect. 



Presents, November 15, 1888. 

 Transactions. 



Baltimore : Johns Hopkins University. Circular. Yol. VII. 



Nos. 66-67. 4to. Baltimore 1888 ; Studies from the Biological 



Laboratory. Vol. IV. No. 4. 8vo. Baltimore 1888 ; Register. 



1887-88. 8vo. Baltimore 1888. The University. 



Peabody Institute. Annual Report, 1888. 8vo. Baltimore. 



The Institute. 



Batavia : Bataviaasch Genootschap van Kunsten en Weten- 

 schappen. JSTotulen. Deel XXYI. Aflev. 1-2. 8vo. Batavia 

 1888 ; Tijdschrift voor Indische Taal-, Land- en Yolkenkunde. 

 Deel XXXII. Aflev. 4. 8vo. Batavia 1888. 



The Society. 



Koninklijke Natuurkundige Yereeniging in Nederlandsch-lndie. 

 Natuurkundig Tijdschrift. Deel XLYII. 8vo. Batavia 1887. 



The Association. 



Berlin: Konigl. Akademie der Wissenschaften. Abhandlungen. 

 1887. 4to. Berlin 1888 ; Politische Correspondent Friedrich's 

 des Grossen. Bd. XVI. 8vo. Berlin 1888. The Academy. 



