160 PROFESSOR WARTMANN ON DALTONISM, 
The only observers who have attempted to classify the dal- 
tonians are MM. Seebeck, Szokalski and Purkinje. 
M. Seebeck has arranged them in two divisions. The first 
comprises those individuals who are more deceived in the degree 
of colouring than in the nature of the colour. The tints which 
they confound more or less are,—light orange and pure yellow; 
dark orange, light yellowish or brownish green and yellowish 
brown; pure light green, gray, brown and flesh colour; rose 
red, green of a more blue than yellow tint and gray; crimson, 
dark green and chestnut brown; bluish green and dirty violet ; 
lilac and blue gray ; azure, blue gray and lilac gray. Their sense 
is very defective for the specific impression of all the colours in 
general ; it is especially so for that of red and consequently for 
green, which is its complementary tint—colours which they di- 
stinguish little if at all from gray; it is further defective for 
blue, which they distinguish very incompletely from gray. Their 
appreciation of yellow is the most correct, although they often 
see less difference between it and the appearance of colourless 
bodies than is the case with the ordinary eye. 
The second division comprises those persons who confound 
light orange, greenish yellow, brownish yellow and pure yellow ; 
bright orange, yellow brown and grass green; brick red, rust 
and dark olive green; vermilion and dark brown; dark carmine 
and blackish blue green; flesh colour, gray brown and bluish 
green; dull bluish gray and gray a little brownish ; dirty rose, 
somewhat yellowish, and pure gray; red rose, lilac, azure and 
gray passing into lilac; crimson and violet ; dark violet and dark 
blue. They have only a feeble perception of the least refran- 
gible rays: this is their most strikingly distinctive character. 
Lastly, yellow is the colour which they recognise best; they 
distinguish red objects a little better, and blue ones a little less, 
than colourless bodies, but above all reds from blues in a much 
less decided manner than persons of the first class *. 
M. Szokalski has devoted an entire chapter of his work + to 
the examination of the defective cases of coloured perception, 
cases to which, with Sommer, he gives the general denomina- 
* Seebeck, Mem. cit., p. 221. An extract from this excellent memoir has 
been inserted in the Jahresbericht tiber die Fortschritte der anatomisch-physio-. 
logischen Wissenschaften, im Jahre 1837, von Dr. Miiller; Miller’s Archiv, 
1838, p. clxxiii. This extract has been republished verbally in the Handbuch 
der Physiologie of the same author. 
+ Miiller’s Archiv, 1842, 
