Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 4: Pla [corr.: Ple] - Wri
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit29465/1466/
1456 VISION. 
for red; pink appeared sky blue by daylight, 
but assumed an orange or yellowish appear¬ 
ance by candle light. Dalton believed that 
the peculiarity in his vision was caused by the 
vitreous humour of his eyes having a blue 
tint : to this point reference will hereafter be 
made. 
According to Professor Wartmann, the 
following are the most common confusions of 
colour, ranged in order of their frequency : — 
1. Deep red with deep blue. 
Indigo with violet. 
Deep blue with violet. 
Bright orange with bright yellow. 
5. Deep brown with deep green. 
Dark blue with indigo. 
Bright brown with bright green. 
Dark red with dark green. 
Rose with bright blue. 
10. Dark orange with dark yellow. 
Bright red with bright green. 
Deep yellow with dark green. 
Dai’k brown with black. 
Bright red with bright blue. 
15. Bright yellow with bright green. 
Bright red with bright yellow. 
Dark red with black. 
Dark red with dark brown. 
Dark green with violet. 
20. Dark red with dark yellow. 
Dark red with violet. 
Bright yellow with bright brown. 
Bright blue with violet. 
25. Dark red with dark grey. 
Dark red with indigo. 
Rose with violet. 
Dark blue with dark grey. 
Dark green with indigo. 
30. Rose with dark blue. 
Rose with indigo. 
Dark green with dark grey. 
Bright orange with bright green. 
White with faint green. 
Putting aside the differences in the bril¬ 
liancy of the tints, it is found that the follow¬ 
ing numbers express how many times each of 
those tints is proportionally seen without 
error. 
Red - - 37 Blue - - 100 
Orange - - 12 Indigo - - 0 
Yellow - - 100 Yiolet - - 0 
Green - - 59 
Wartmann has given* a very interesting 
account of his experiments on the vision of 
Louis D-. This individual did not per¬ 
ceive any great difference between the colour 
of the leaf and that of the ripe fruit of the 
cherry ; he confounded that of a sea-green 
paper with the scarlet of a riband placed close 
to it. The flower of the rose seemed to him 
greenish blue, and he called the ash colour 
of quick lime light green. The appearances 
presented by a solar spectrum were as follows, 
_the coloured bands, brilliant and distinct, 
extended a length of about 0-102'. D- 
perceived four colours only, blue, green, yel¬ 
low and red. He limited the blue part exactly 
to the space occupied by the violet, indigo and 
blue : he called the green and yellow bands, 
less an interval of 0-002' towards the orange,- 
green ; he called that band of 0 002 , and a 
fraction of the red 0-012' in breadth, yellow; 
* Taylor’s Scientific Memoirs, vol. iv. p. 173. 
lastly, the remaining 0'008' of red appeared to 
him of a red difficult to define. By refracted 
light the results were nearly the same, thirty- 
seven plates of glass exhibiting only four 
different colours in various intensities. 
When examined by polarized light, it seems 
that on the one hand he did not appreciate 
the equality of intensity of two complementary 
colours as did ordinary vision ; but he found 
a total and abrupt difference when colours 
passed at once from the finest red to very 
rich deep blue, a distinction far from being 
marked to others. 
His visual organ was unable to perceive the 
different mixtures of red which accompany 
blue to make it pass into purplish violet. 
This precise circumscription of the consti¬ 
tutive domain of a colour is a fact which, in 
the opinion of Professor Wartmann, was new 
and worthy of being remarked. 
Whilst a series of these experiments with 
olarised light were going on, the sun, which 
ad been obscured, suddenly shone out, and 
D- declared that the colours imme¬ 
diately assumed a different tint to his sight, 
all reddening in a sensible manner, so that 
he called red that which he had before named 
green and ill-defined blue, whereas the Pro¬ 
fessor saw no other change in the colours 
than an increase of their brilliancy and strength. 
Wartmann then submitted the patient to 
experiments to ascertain his perception of the 
complementary colours, and the result showed 
that although his eyes were not insensible to 
them, the colours which appeared to him 
complementary were not the same as those so 
regarded by the normal eye. The Professor 
then painted a human head, giving to each 
part a complementary colour. Thus the hair 
and eyebrows were white, the flesh brownish, 
the sclerotica black, the lips and cheeks green. 
When asked what he thought of the bead, 
D- replied that it appeared to him na¬ 
tural, that the hair was covered with a white 
cap little marked, and that the carnation of the 
cheeks was that of a person heated by a long 
walk. 
There are a certain number of cases of in¬ 
sensibility to colours which have been quoted 
by all writers on the subject. We shall there¬ 
fore content ourselves with merely referring 
to them*, describing a few well marked and 
uncommon instances less generally known. 
Dr. Boys de Loury f has published the 
particulars of a M. H-, who was obliged, 
on account of his defective sight, to aban¬ 
don the profession of a dyer. His principal 
colour was yellow. The brilliant yellow of 
the apricot and deep brown of the chesnut 
were only distinguished as varieties of shade. 
All dark hues were called black; scarlet ap- 
* Cases of achromatopsy are detailed as follows : 
— Phil. Trans, vol. lxvii. p. 260, vol. lxviii. p. 611 ; 
Edinb. Phil. Trans, vol. x. 253 ; Spurzheim Phren¬ 
ology, 3d ed. p. 276 ; Combe’s Syst. of Phrenology ; 
Trans. Phren. Society, p.222 ; Trans. Med. Chir. 
Society, vol. vii. p. 47 7, vol. ix. p. 359 ; Glasgow 
Med. Journal, vol. ii. p. 12; Edinb. Phil. Journal, 
vol. vi. p. 135. 
, f Revue Médicale, Nov. 1843.
        

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