SECTIONAL TRANSACTIONS.— J. 407 



extension is unlikely for a long time to come. Consequently the writer 

 offers an approximation to it by a certain line of argument. 



It is considered that the total sensation reaction to tropical and sub- 

 tropical climates is made up of two parts : one, which can be named physical, 

 tends to be marked by such physical signs — in the medical sense — as varying 

 degrees of perspiration ; the other is a neural reaction ranging from lethargy 

 in humid conditions, through varying degrees of exhilaration in moderate 

 humidity, to excitement and irritability in arid conditions. 



The writer's idea is that for various places a mean of daily temperatures 

 and humidities at, say, noon be obtained, that these be converted to degrees 

 of physical and neural reaction by his method, and that the results be 

 plotted in diagram form for the purpose of comparison. 



An example of such a comparison between two places is provided. 



Dr. S. J. F. Philpott. — Resemblances between fluctuations in curves of 

 mental output and of chemical change (3.30). 



It is suggested that fluctuations sometimes found in curves of chemical 

 change are of the same nature as those met with in curves of ' fluctuation 

 of attention.' 



Attention waves are geometric in the sense that times at which successive 

 crests (or troughs) occur are in geometric progression. They thus seem 

 to have constant period when plotted against the log of time. All log 

 periods are whole number multiples of 0-0016. Phase also is constant, all 

 trough sequences converging on a common trough at the time 



T = 4-076 X io" 23 seconds 



There is no predicting when any given wave will appear. As it were, 

 the person concerned takes a random handful from a pool of possible ele- 

 mentary waves with which to constitute his curve of any given experiment. 

 The most obvious periods in a curve are apparently of repeat cycle signifi- 

 cance. That is to say, they tend to be highly factorisable multiples of the 

 unit, as, e.g., 108, 180, 252, etc. So that although no two curves are ever 

 alike in minor detail (depending as they do on randomly chosen elementary 

 waves), there are nevertheless but few major measures in practice, namely 

 the highly factorisable periods just mentioned. 



Certain chemical curves are presented, the reaction being that of normal 

 hydrochloric acid on aluminium in the presence of platinum and a trace of 

 gelatin. No two are alike in minor detail, but the measures made are those 

 commonly occurring on the mental side, whether in respect of period or 

 trough sequences. It seems clear that the unit of periodicity, the common 

 trough point, and the element of random sampling hold both for mental 

 and chemical fluctuations. 



Dr. T. G. Maitland. — Visual factors of vertigo (4.15). 



When our equilibrium breaks down after certain kinds of imposed move- 

 ment, such as being turned in a revolving chair, it is the failure of the 

 kinetic and postural attempts at compensation which cause ' special ' 

 vertigo. The subsequent illusion of subjective or objective turning that 

 characterises this type of vertigo is largely due to the persisting ' to and fro ' 

 movement of the eye, called ' ocular ' nystagmus. 



