On Coloured Vision produced by Santonine. 91 



this peculiar action, almost at the same time, by myself and 

 by M. de Martini, of Naples. I shall proceed to detail the 

 more remarkable of these experiments. 



At a quarter past two o' clock, on the 5th February, 1859, 

 I took five grains of Santonine, and waited anxiously for the 

 desired effect, namely, the production of coloured vision. For 

 a considerable time I experienced nothing extraordinary, and 

 began to think the experiment a failure. For, as I never have 

 taken medicine of any kind, except now and then as an expe- 

 riment, my constitution is particularly sensitive to the influ- 

 ence of any chemical agent. About five o' clock, however, I 

 fancied that the white curtains of my room had a very pale 

 greenish tint. I attributed the effect to imagination, and went 

 out. At six o'clock I returned, the gas was lighted, and the 

 fire was burning brilliantly on the hearth : a singular pheno- 

 menon now presented itself. The fire and the glass globes 

 which surrounded the gas-jets appeared of the most gorgeous 

 yellow it is possible to imagine. It was a greenish-yellow, ex- 

 ceedingly rich and brilliant, resembling some kinds of bur- 

 nished gold. It was the colour of chlorine gas, but much 

 more intense. I communicated these effects to the persons 

 near me, who, seeing the objects as usual in their natural 

 colours, could not realize what I experienced. Everything in 

 the room that was white and strongly lighted (as the table- 

 cloth for instance) appeared to me of the most brilliant 

 greenish-yellow, the flames of the gas-jets and the fire were 

 most remarkable in this respect. The other objects of different 

 colours, red, blue, yellow, appeared still red, blue, or yellow ; 

 it was only white objects and flames that appeared of that 

 peculiar greenish-yellow tint alluded to ; but, doubtless, all 

 tints must have been more or less affected by the state of my 

 vision. 



It is, perhaps, needless to add that I experienced no dis- 

 agreeable effects, at least not at the time I experienced coloured 

 vision, though some time before I felt slightly bilious. As 

 the colour seen was, as above stated, nearly that of chlorine 

 gas, I prepared a bottle of this gas and held it to the light ; it 

 appeared of its ordinary greenish-yellow tint, but much more 

 intense than usual. The flame of a gas-jet appeared, in these 

 experiments, of a bright greenish-orange, very rich, and the 

 lower portion of the flame, where a vivid rim of blue light is 

 observed in ordinary circumstances, appeared to me of a 

 beautiful bluish -green. 



These effects continued without intermittence during the 

 rest of the evening; they began to diminish about half-past 

 ten, but were very distinct, though weak, at twelve o'clock, 

 and even until two o'clock at night, when I retired to 



