4 o8 SECTIONAL TRANSACTIONS.— J. 



General vertigo is distinguished from special vertigo by the absence of 

 this illusion of turning ; in its place there is an illusion of recession and 

 approach or undulating of objects in the visual field. This illusion is due 

 entirely to a condition of ocular imbalance with its constantly recurring 

 efforts at focusing. 



Inasmuch as these examples of vertigo are extremely complicated in 

 their somatic causes, the third type of vertigo offers a simpler example for 

 analysis. 



It, also, is characterised by an illusion of movement of objects, and some- 

 times of oneself, not very dissimilar from that of special vertigo, but is 

 never severe and is always of short duration. In this case the cause is 

 entirely visual. When a uniform succession of objects moves across the 

 field of vision, sufficiently monotonous not to excite close attention, the 

 eyes will react by ' optic ' nystagmus. If this succession of passing objects 

 continues sufficiently long, there is left a residual and persistent nystagmus 

 after the objects have passed out of the line of vision. The illusion which 

 then ensues is an apparent movement of the stationary background, and 

 a momentary sense of vertigo. 



Another type of post optic nystagmus bearing a close relation to the last 

 is miner's nystagmus. The excitation is also visual, the conditions for its 

 persistence are also those of mental distraction. The difference is that both 

 components of miner's nystagmus are fast, i.e. fixation reflexes. 



Monday, September 14. 



Dr. R. W. Pickford. — Conclusions of a study of group psychology (io.o). 



This paper deals with some results of an attempt to approach the 

 history of painting from the points of view of the biology and psychology 

 of groups. A strictly scientific treatment of advanced cultures along these 

 lines has not often been attempted. The phases of the history of painting 

 which have been studied are : Barbizon and Glasgow groups, Pre-Raphaelites, 

 Mogul miniature painters, Bushman art, the Russian icon and the work of 

 Chardin, Goya, Daumier and Cezanne. The following points are dis- 

 cussed : transmission of culture by group contacts, borrowing and grafting, 

 and the omissions involved in these changes ; constructiveness, conserva- 

 tion and decay in group life. It is interesting to find that these changes 

 take place in advanced cultures in much the same way as they do in primitive 

 cultures. 



Discussion on The reform of the examination system (10.45). 



Dr. Ll. Wynn Jones. — The reform of the examination system. 



One stream of criticism by practical schoolmen has been directed against 

 the pernicious effects of examinations on curricula, and hence on ' culture ' 

 — which is an ambiguous term and is moreover in a state of flux. Reformers 

 of curricula have usually to expect small profits and slow returns, cf. the 

 need of psychological background, for would-be clergymen, physicians, and 

 lawyers. The other stream of criticism by psychological testers is con- 

 cerned with the content and form of examination papers, errors of marking, 

 or failures to take into account variations in the performances of individual 

 candidates. Here, also, the carrying out of essential reforms shows a lag. 



