94 Dr. E. Hose on the Doctrine 



The chaos of contradictions in the older and even in the 

 newest statements as to defects in the sense of colour, colour- 

 blindness, and Daltonism, is partly explicable by the mode of 

 investigation, and partly by the circumstance that the two chief 

 diseases have not been discriminated. 



Both may occur together, as in the highest degree of the san- 

 tonine stimulus, in acute yellow atrophy of the liver, nocturnal 

 blindness, congenital colour-disease. All Daltonists are colour- 

 mistaken ; from the result of the above-mentioned spectrum 

 investigation they are probably all colour-blind ; hitherto, it is 

 true, it has not been shown in all cases. 



As Mr. M (and others) shows, congenital colour-blindness 

 occurs without colour-mistake, just as the santonine-stimulation 

 often leaves yellow-si ghtedness, and does not attain a violet 

 vision. Just so among five cases of colour- diseases after liver 

 complaints, there was only one, which was quickly fatal, in which 

 colour-mistake supervened, and that only momentarily. The 

 other cases went no further than colour-blindness (two cases of 

 catarrhal jaundice, one of hypertrophy of the liver, one of cancer 

 of the liver). It follows thence that sensational colour-mistake 

 is the more serious complaint. Further experiments must show 

 whether, in the case of jaundice, by diagnosis of the kind of 

 colour-disease, the gravity of the case can be previously deter- 

 mined, as almost seems to be the case. 



Colour-mistake may in general be divided into simple and 

 complete. One who sees violet in the santonine stimulation is 

 simply colour-diseased; of the great number of colours he 

 confounds, there is only one complementary pair of colours. 

 This is the case with those Daltonists whom I have called plane*, 

 because their congenital colour-system may be represented by a 

 plane, just as that of a healthy man by a cone. Different 

 from these are the Daltonists whom I have called " linear," as, 

 for instance, Messrs. Kf, LJ, and 0, and probably also the 

 patient with disease of the kidneys whose examination remained 

 incomplete, — linear, because their congenital mass of colours can 

 be represented by a line. 



It is characteristic of these completely colour-mistaken persons, 

 that to them all pairs of complementary colours, of a determinate 

 different intensity, always seem equal; to a singly colour-blind 

 only one pair. 



All colour-mistaken persons have this in common, that no two 

 have hitherto considered a pair of colours agreeing in intensity 

 and tone to be equal. 



* Grafe's Archiv, vol. vii. p. 92. 

 f Ibid. p. 98. + Ibid. p. 99. 



