Prof. Blumcnbach on the Xanthoopid of Jaundiced Persons. $65 
Mercurialis * * was the first, in as far as I know, who called this 
assertion, regarding the yellowish vision of those who labour un- 
der icterus, in doubt ; and in later times Haller t } and Mor- 
gagni j, among others, have been similarly inclined. 
Lastly, a middle opinion between the two has been held 
by many after Hoffmann §, Durazzini, Buzzi, and Percival |[, 
who acknowledged, that the yellow vision in question does in- 
deed occur in some cases of icterus, though rarely, and who 
placed the fact beyond dispute by accurate investigation, as well 
as occasionally by the anatomical dissection of the eyes of pa- 
tients who died of jatmdice. 
But, on consulting all these opinions with care, that rarer 
Xanthoopia (as it may be called) of jaundiced persons, seems to 
be in this condition, that it supposes at first a yellowish tinge in 
the pellucid media which transmit the ra^s of light, especially of 
the aqueous humour and crystalline lens ; then a not so gentle, 
but more sudden attack or increase of the disease ; and, lastly, 
both a vivid perception in the sensorium and application of the 
mind. But as these seldom happen at once in icterus, we can 
easily comprehend why very few patients in that disease com- 
plain of the yellow tint of objects. On the contrary, I knew a 
lady of excellent talents and accomplishments, who, on a sudden 
and severe attack of icterus, saw at first linen of all kinds, 
towels, &c. of a livid or dusky hue, and as if they had been ill 
washed, or not properly bleached. But those, upon whom the 
disease seizes slowly, advancing as it were step by step, no more 
experience this yellow hue of objects than old people do, in 
whom we have known the crystalline lens become livid in very 
advanced age. Should this tinge take place in one eye only, the 
other remaining uncontaminated, that diversity of colour in white 
and shining objects, would be no less easy of observation, than in 
* Variar. Lection. 1, vi. p. 357. of the Paris ed. of 1585. 
*f* Ad Boerhaav. Praelect. t. vi. 1. c., and his Element. Physiol., and v. p. 488. 
t De Sed. et Caus. Morbor. &c. ep. xxxvii. art. 8. vol. ii. p. 74. of the 
Venice ed. of 1761. 
§ See his Works, v. iii. p. 302. 
]| See his Works, Literary, Moral and Philosophical, ed. of 1807. v. ii. p. 228. 
