PROFESSOR WARTMANN ON DALTONISM. 157 
a more rational one*. This case appears to be well known, 
and I have no occasion to dwell upon it here. 
But there have long ago been ascertained facts of abnormal 
coloured vision in which ¢he affection is habitual and permanent. 
These may be classed in two distinct categories :— 
1. That of persons in whom a// coloured impressions are con- 
stantly defective from a disordered condition. Some perceive 
the flame of a candle surrounded by an iris,—others think that 
all objects near them have a yellow, green or blue tint, &c. 
Their malady has been described by oculists under the name of 
Chromopsis or Chrupsiat. 
2. The category of individuals incapable of distinguishing from 
one another a variable number of colours, as there are some 
who cannot distinguish the intervals of musical tones; they con- 
found blue with violet, light blue with light green, dark green 
with brown, sometimes rose colour with light yellow, &c., al- 
ways distinguishing the pale tints from those which are bright. 
The denominations of Achromatopsis{t, Chromatopseudopsis, 
Chromatometablepsis, Akyanoblepsis§, &c., have been employed 
by writers to designate the different cases which they have ob- 
served and described in a manner more or less confused. 
* J. Plateau, Mem. Ac. des Sci. de Brux., tom. viii. 1834. See also the 
remarkable memoirs of Professor Fechner in Pogg. dunn. der Phys. und Chem. 
1840.—L. W. [See also the Lond. and Edinb. Phil. Mag., Dec. 1839, vol. xv. 
p. 441.—Ep_] 
+ The Chrupsia takes place in some cases of jaundice. Boyle relates that 
persons in the plague saw all objects, and even their clothes, as surrounded 
with rainbows (Eaperimenta de Coloribus, p.1). Under the influence of a 
very lively fear, it is said that persons see gray or blue prevail in the external 
colouring. Dr. Parry mentions an old general who, in the evening before the 
candles were lighted, and in the morning for the first hour after he went out, 
imagined all white objects to be of a deep orange colour approaching to scar- 
let (Collections from the Unpublished Medical Writings of C. H. Parry, M.D., 
vol. i. pp. 560, 568, 569. Lond. 1825). Dr. Mackenzie mentions a person who 
saw all objects as if tinged with green, in consequence of a wound of the cornea 
with prolapsus of the nasal part of the iris (on the Diseases of the Eye, p. 862). 
Five persons having poisoned themselves with roots of henbane, were treated, 
some by Yartar. stibiat., and the others by Theriaca; they were cured, but they 
saw for three days everything around them of a scarlet colour. (Letter of Dr. 
Patouillat in the Phil. Trans., vol. xxxix. p. 446. 1738.) 
t Achromatopsis, properly speaking, is the absolute impossibility of distin- 
guishing colours. ‘Those who are affected with it in general see everything as 
gray: they are very few in number. According to Professor Jiingken, this 
imperfection occurs especially in individuals with gray eyes, rarely in those who 
have the iris brown; it dates commonly from the birth, and, in this case, it is 
hereditary and incurable; but it is manifested also gradually and as a symptom 
of cataract, of glaucoma and of amaurosis. (Die Lehre von den Augenkrank- 
heiten, p. 841. Berlin, 1832.) 
§ Goethe, Farbenlehre, tom. ii, p. 105. 
