LENS CURRENTS 



57 



quite fresh from the sea. I subsequently made similar observa- 

 tions on the eyes of octopus, on sheep's eyes fresh from the 

 slaughter-house, and on the eyes of recently killed cats and 

 rabbits. 



" The point that was most striking in these first observations 

 was the great endurance of the reaction in the crystalline lens 

 as compared with its rapid disappearance from the remaining 

 tissues of the eyeball and from the skin, and with the rapid 

 disappearance of the direct electrical excitability of muscle. I 

 should, as an outcome of these observations, look for the last 

 sign of life of a fish by testing the crystalline lens, whereas in 

 the case of man I should test a piece of skin. The reaction as 

 far as I have yet seen has been completely absent from frozen 

 fish (salmon) as received from London fishmongers. Its normal 

 direction in the lens is ' negative,' i.e., from external to internal 

 pole. It is abolished by heat (70) and by pressure. A typical 

 pair of responses is illustrated by the following record : 



FlG. 25. Codfish. Antidrome and homodrome responses of the isolated lens, 

 from anterior to posterior pole, of - 0.0009 an d - 0.0022 volt respectively. 



