166 PROFESSOR WARTMANN ON DALTONISM, 
day, and bright red by candle light. For the rest, he distin- 
guishes very well black from white. 
Dr. Nicholl has recorded the examination of two remarkable 
daltonians. One*, a child eleven years old, did not call any 
colour green; he called dark green, brown; light yellow, yellow ; 
dark yellow and light brown, red; pale green, light red; light 
red and rose-colour, light blue; the red, red; light blue and 
dark blue, blue. The solar spectrum presented to him only red, 
yellow and purple. His mother and his four sisters had their 
sight correct, but that of his maternal grandfather and some 
brothers of the latter was imperfect. 
The second subject studied by Dr. Nicholl} was a man aged 
forty-nine. Like the preceding, he had gray eyes and a yellow 
tint around the pupil. He cannot distinguish green from red. 
He perceives scarlet colour, but he calls dark green brown; 
light yellow, yellow; dark yellow, light brown; light red, rose 
and violet, blue; he appreciates very well dark blue and black. 
The rainbow appears to him yellow in the centre and blue to- 
ward the edges; crimson curtains appear to him blue by day 
and red by candle-light. To his eye grass is red, and red fruits 
are of the same colour as the leaves of the trees which bear them. 
He has not a clear notion of the complementary colours. Lastly, 
he sees further and more distinctly in the dark than his relatives 
and friends. 
Dr. Colquhoun has also described two cases very well cha- 
racterized{. The first is that of an educated person, who has a 
decided taste for paintings, and has himself described the pecu- 
liarities of his vision :—“ 1 ought to state at the outset, that I 
do not invariably confound the colours to the distinction between 
which my eye is generally insensible. Thus the brilliant reds 
and greens in the plumage of certain birds, and in some fruits, I 
can always appreciate with perfect accuracy, whilst to the gene- 
rality of eyes the difference between such colours and those 
which I am certain to confound is not perceptible; neither can 
I myself explain in what the peculiarity consists, which thus 
enables me to appreciate their quality truly. 
* Account of a case of curious imperfection of Vision, by Whitlock Nicholl, 
Medico-Chirurgical Transactions of London, vol. vii. p. 477. 
+ Account of a case of defective power to distinguish colours, by Whitlock 
Nicholl of Ludlow, Medico-Chirurg. Trans. of London, vol. ix. p. 359. 
t Glasgow Medical Journal, vol. ii. p. 12, 1829.—I am indebted to the 
kindness of Dr. Coldstream of Leith for the manuscript communication of this — 
article, inserted in a collection very rare on the Continent. 
