EEVIEWS — RESEAECHES ON COLOFE-BLINDNESS. 147 



dant proof of its existence ; and that, between the eye thus abso- 

 lutely destitute of perception of colour and the normal eye, which is 

 only insensible to the distinction between faint shades of contiguous 

 colours, there exists a great variety of sensibility to colour in different 

 persons, commencing with those rare cases which confound all colours 

 indiscriminately, passing on to others, still rare, which confuse one of 

 the primaries with another and with all composites, or which are 

 sometimes insensible to the primary red ; then to more frequent 

 cases of confusion of one or more composites, and thus terminating, 

 though by no marked definition, in the normal eye. To desiguate 

 these various grades of defect the appropriate term colour-blindness 

 has been adopted, supersediug (we hope) the name of Daltonism, 

 which that illustrious chemist had unenviably suggested to Continen- 

 tal savans by being one of the first to call attention to the subject 

 through a description of his own case. The term, however, must be 

 understood as restricted to cases where the deficiency is decidedly 

 marked (since we are all more or less colour-blind), and does not 

 properly include such cases as consist merely in a defective memory 

 of colours, in which the inability to name any particular colour pre- 

 sented does not result from inability to distinguish between it and 

 another when simultaneously contrasted to the eye. 



Previous to the publication of the work which is the subject of 

 this article, information on this interesting subject was not readily 

 accessible, and was sufficiently scanty : a couple of admirable 

 memoirs by "Wartinann; descriptions of particular instances scat- 

 tered through the Transactions of scientific societies ; the investiga- 

 tions of Seebeck, and the digests of Brewster, Herschel, and Moig- 

 no, comprised nearly all that was then known. Fortunately the sub- 

 ject attracted the attention of Dr. George Wilson, the gentleman 

 whose recent appointment to the chair of Technology in the Univer- 

 sity of Edinburgh, and the Directorship of the National Industrial 

 Museum, has been hailed with pleasure by the scientific world; and 

 to his exertions we owe not only a vast accession of original facts 

 and cases, but the clear and full exposition of the whole subject con- 

 tained in the work before us. Dr. "Wilson appears personally to 

 to have examined above seventy marked cases (besides numerous 

 others communicated to him from all parts of the country) occurring 

 in all conditions of life, and sometimes presented in a manner which 

 conveys to the normal-eyed a sense of the ludicrous. Thus, to select 

 a few instances almost at random, Mr. N. (who thinks his blindness 

 an advantage to him as an amateur artist) says, " I have sometimes 

 attempted a coloured landscape, relying upon a friend to select the 



