722 TRANSACTIONS OF SECTION I. 



7. Fourth Report on the State of Solution of Proteids. 

 See Reports, p. 428. 



MONDA Y, AUGUST 6. 



The following Discussions took place and Papers were read : — 



1. Discussion on the Physiological Value of Rest, opened by Theodore 



Dyke Acland, M.D. 



2. The Neuron Theory : Fatigue, Rest, and Sleep). 

 By Dr. W. Bevan-Levvis, M.Sc. 



The author believes, despite the adverse views of Apathe, Bethe, Dogiel, and 

 Donuagio, that the neuron conception has come to stay with us. After brief 

 reference to the grounds of dissent by the above neurologists, he defined the older 

 views respecting the constitution of the nerve-cell, contrasting it with the neuron 

 theory as revealed by modern microscopic technique. He discussed the disposition 

 of neuro-fibrils and the probable course of nerve-currents therein, alluding to the 

 views of Berkeley and Cajal on the synapse. The law of dynamic polarisation 

 enunciated by Cajal is, in the author's opinion, not absolute. He would regard 

 the neuro-fibrils as possibly stimulated from two sources : (a) From their termini 

 in the gemmules, forming an apparatus for isolated stimulation ; (6) in the mesh- 

 works within the cells, by products of cell metabolism, possibly by nuclear 

 influences, and certainly by toxic agencies entering the cell from without — a 

 mechanism for more massive results. Contrary to Sir W. Qowers, he still 

 inclines to regard the cell as a storehouse of energy, and emphasised the 

 importance of the chromophilic material of Nissl in cell metabolism, and, as 

 suggested by Marinesco, as serving to increase the potential of the nerve-current. 

 Lugaro's elaborate work, which supports the view that the nerve impulse 

 originates as the result of a physico-chemical process at the synapse was alluded to. 

 He proceeded to indicate how bodily tatigue and mental fatigue is correlated, and 

 the fallacy of the view that gymnastics are not restoratives for mental fatigue. 

 In defining the nature of the change found in the nerve-cell after fatigue, he 

 alluded to the role of the 'scavenger-cell.' Waiving the several less secure 

 theories of sleep he discussed Duval's theory of dendritic contraction, based on 

 the known features of cell amoeboidism. Personally he dissents from this view 

 of dendritic contraction, but favours that of gemraule retraction alone; and difl'ers 

 from Lugaro in regarding their expansion as the incident of active mental states, 

 and not their recession as taught by that neurologist. Apart from terminal arbor- 

 isations and their synapses, a further apparatus for originating the nerve impulse 

 is found in the functionating of contiguous dendrites of separate neurons — a view 

 which he bases on histological details of the ueuro-fibril structure —and he lays 

 great emphasis on the fixed anatomical juxtaposition of nerve-cell groupings. 

 Dealing with brain-fag in school children be concluded by postulating the following 

 conclusions : — 



(1) The necessity for recognition of diurnal variations in the tide of mental 

 acquisitiveness. 



2) The study of the fatigue-curve and the importance of interpolated periods 

 of rest in its modification. 



(3) The residual fatigue should be watched for if not compensated for by the 

 previous night's rest. 



(4) The enormous metabolic activity ot this period of the child's life should 

 always be borne in mind. 



(5) The importance of the central nervous system as the controlling factor in 

 general metabolism. 



