492 



Mr. G. F. Dowdeswell on the Changes of [Jan. 18^ 



physical nerve change, so that the expression would become a physio- 

 logical instead of a psychical one. 



Fechner regards the liminal intensity o£ an increment of sensation as 

 an invariable unit, whilst, as is clearly shown, the liminal increment of 

 the stimulus varies as a function of the stimulus already existing. This 

 is an entirely arbitrary convention. If we regard the value of the liminal 

 increment of sensation as a variable dependiug for its value on the 

 already existing sensation, we may take 



2K r = K S, or AS, 

 instead of Fechner's expression 



Jdv 

 - = Klog^^ = S, 



where x represents the stimulus and S the sensation. 



This relation is further borne ont by the beautiful experiments of Mr. 

 Dewar and Dr. McKendrick, which show that the electric variation in 

 the natural current of the eye varies as the square root of the intensity 

 of the stimulus ; although those authors have attempted to make their 

 results accord with Fechner's formula, they have only done so by the 

 erroneous use of one of M. Delboeuf's constants, which gives a very wide 

 range of arbitrary adjustment. 



January IS, 1877. 



Dr. J. DALTON HOOKER, C.B., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered for 

 them. 



The following Papers were read : — 



I. Note on the Changes of the fixed Corpuscles of the Cornea 

 in the Process of Inflammation.-''' By G. F. Dowdeswell, 

 B.A. Communicated by J. Burdon Sanderson, M.D.^ 

 F.B.S. 



[Plate 10.] 



Since the discovery by Von Eecklinghausen of the immigration of pus- 

 corpuscles into the substance of the cornea in inflammation, several 



