194 



Dr. A. D. Waller. On the 



[Oct. 23, 



" On the ' Blaze-currents ' of the Crystalline Lens." By A. 1). 

 Waller, M.1X, F.K.S., assisted by A. M Waller. Eeceived 

 October 23 — Eeacl December 4, 1902. 



(From the Physiological Laboratory of the University of London, S.W.) 



In the course of investigation of the effects of light and of electrical 

 excitation on the frog's eyeball, I came to the conclusion that tissues 

 other than retinal are coeffective in the response to strong induction 



hocks, and proceeded therefore to look for blaze-currents in other 



iving tissues.* 



* ' Phil. Trans.,' B, 1901, vol. 194, p. 185. 



The following extract from my note book of 1900 gives instances in which the 

 reaction of the anterior half of the eyeball "was observed to exceed that of the 

 posterior half. 



Frog's eyeball, entire and bisected. 



Excitation by single break shock from Berne coil. 

 Strength of 



excitation. 

 1000 + 

 1000- 

 Another eyeball- 

 5000 + 

 5000- 



5000 + 

 5000- 



Whole eyeball. 

 + 0*0013 volt. 

 + 0-0026 „ 



+ -0017 „ 

 -0-0013 „ 



Dog's eyeball. 



-0-0024 volt, 

 -0-0008 „ 



Posterior half. 

 Ml 



+ -0002 

 + -0002 



4 hours post mortem. 



Nil 



Anterior half. 

 + -0030 volt, 

 + 0-0033 „ 



-0-0020 ,. 

 -0*0040 „ 



■0-0030 

 0-0004 



The cornea alone gave —0 *0030. 



-0-0006. 

 The lens alone gave nothing. 



In these early experiments (November 1900) no particular care was observed to 

 avoid compressing the eyeball, and the response of the lens was therefore not 

 obtained. 



Frog's Eyeball. Tested by the ABC method. B = fundus. A = cornea. 

 C is midway between A and B. Excitation by single break shocks of Berne coil 

 at 1000, supplied by two Leclanche cells. 



Excitation 



Excitation + 



Total response 



Partial response 

 between C and A 



Partial response 

 between C and B 



+ -0052 



-0025 



C 



+ -0008 



'0138 



-0050 



c 



-0015 



The particular point that aroused my attention in the case of the 

 eyeball was the fact that the anterior half of the eyeball was some- 



