l^O Sir D. Brewster on Colour Blindtiess. 



which it misapplies, and as one of the worst examples of 

 vicious nomenclature. The name was first imposed by Prof. 

 Prevost of Geneva, and Prof. Wartmann has continued it on 

 the sole ground that it has for forty years been employed in 

 oral instruction in the academy of that city. Dr. Whewell's 

 name of Idioptcy or Idiopts is clearly inadmissible, and we 

 cannot speak more favourably of the name Achromatopsie, used 

 by Purkinje; Akyanoblepsie, used by Goethe; Chromatopseu- 

 dopst/i used by Sommer and Szokalspi ; and last and worst of 

 all, Chro7natometablepsie ! We have used the word Colour 

 blindtiesSi because it indicates simply blindness to one or more 

 colours*. 



The following is Prof. Wartmann's recapitulation of the 

 principal results of his able and interesting memoir : — 



1. Daltonism has not been studied by the ancients. 



2. It has been found only in individuals of the white race. 



3. There are very many varieties of the affection, from per- 

 sons who see only black and white to those who in candle- 

 light confound approximating shades of blue and green. 



4. There are more Daltonians than is generally believed. 



5. The female sex furnishes a very small proportion. 



6. In certain cases they may be recognised by external signs. 



7. There are as many Daltonians with blue as with black eyes. 



8. Daltonism is not always hereditary. 



9. It does not always affect the males of the same family. 



10. It does not always commence at birth. 



11. The Daltonians do not judge as we do of complemen- 

 tary colours. 



12. Several of them are not sensible to the least refrangible 

 rays. 



13. They see, as we do, the lines in the spectrum disco- 

 vered by Fraunhofer. 



14. They do not judge as we do of the contrast of colours. 



15. Daltonism does not arise from a vicious conformation of 

 the eye, or any coloration of the humours or the retina. 



16. We may alter the state of Daltonism by very simple 

 means. 



17. Daltonism has its origin in a defect of the sensorium. 



In treating of the differences of colour seen by each eye, 

 Prof. Wartmann ascribes to M. Quetelet, or rather quotes from 

 him. Dr. Smith's of Fochabers beautiful experiment, originally 

 described and fully discussed in this Journal (Phil. Mag. S. 3. 

 vol. i. p. 249, 1832, and vol. ii. p. 168) ; and in his observations 



[* A paper on a case of colour blindness by the late Mr. G. Harvey, 

 was reprinted from the Edinburgh Transactions, in Phil. Mag. S. 1. vol. 

 Ixviii. p. 205.] 



