OR COLOUR BLINDNESS. 159 
ip 
ANTERIOR OBSERVATIONS. 
§ 1. Of the Classifications. 
The facts of daltonism hitherto described are not very nume- 
rous. We find no mention of them in our best treatises of 
French physics (that of M. Péclet excepted), nor in the works 
of Priestley * and of Scemmering‘, nor in those of Burdachf, of 
Tiedemann §, of Richerand ||, of Majendie{, &c., on physiology. 
Professor J. Miiller does not speak of it in his great Treatise of 
the Comparative Physiology of Vision in Man and Animals**, 
and in his ‘ Manual of Human Physiology ++ he only cites the 
observations of M. A. Seebeck, jun., which will be noticed 
hereafter. The interesting memoir of the latter{{, a work by 
M. Szokalski, which I have not suceeeded in procuring §§, a 
chapter of the work of Mackenzie on the Eye||||,—these, with a 
few lines by Goethe, and two or three notices scattered in the 
‘Philosophical Transactions’ and in the English journals of 
medicine and physiology, are nearly all that I have been able 
to collect for the purpose of tracing the history of my subject. 
* Dr. J. Priestley. The history and present state of discoveries relating to 
Vision, Light and Colours, vol. ii, Lond. 1772. 4to. 
ft Sam. Thom. von Seemmering. Ueber einige wichtige Pflichten gegen die 
Augen. 5¢ Aufl, Frankf. a M. 1819. 
{ Burdach. Die Physiologie als Erfahrungswissenchaft, mit Beytrdgen von 
Karl Ernst von Baer und Heinrich Rathke. Leipz.1835. 5 vols. 8vo. 
§ Tiedemann. Physiologie des Menschen. 2 vols. 8vo. Darmstadt, 1830-36. 
|| Richerand. Nouveaux Eléments de Physiologic. 10¢ edit. Augmentée par 
M. Bérard ainé. 3 vols. 8vo. 1833. 
{ Majendie. Précis Elémentaire de Physiologie. 5¢ edit. Bruxelles, 1838. 
8vo. 
** J. Miller. Zur vergleichenden Physiologie des Gesichtssinnes des Mensch- 
en und der Thiere. 1 vol. 5vo. Leipzig, 1826. 
++ J. Miller. Handbuch der* Physiologie des Menschen, tom. ii. p. 392. 
Coblentz, 1838. 
ti A. Seebeck. Ueber den bei manchen Personen vorkommenden Mangel 
an Farbensinn. Pogg. Ann. der Phys. und Chemie, Bd. xlii. p. 177 (1837). 
I ought to say that this work, of the existence of which I was ignorant when 
this Memoir was presented to the Société de Genéve, has been of great use to 
me in completing it for publication. M. Seebeck has been so obliging as to 
give me a copy of it, to which he had added specimens of coloured papers 
which he used in examining and classing a great number of daltonians. 
§§ Its title is, ssai sur les Sensations des Couleurs. Bruxelles, 1840.—See 
Bericht tiber die Fortschritte der Physiologie des Gesichtssinnes, in den Jahren 
1839 bis Mai 1842, vom Medicinalrath Dr. Tourtual zu Minster, p. lii. 
Miiller’s Archiv fiir Anat. Physiologie und wissensch. Medicin for 1842. 
\\\| W. Mackenzie. A Practical Treatise on the Diseases of the Eye. Lond. 
1835, ed. 2. 8vo. chap. xx. p. 860. 
