172 PROFESSOR WARTMANN ON DALTONISM, 
servations of daltonism known to me, in which the colour of the 
iris has been noted, I find that the two tints are in equal num- 
bers. M. Seebeck also rejects this opinion, which is founded on 
the fact that the majority of the cases examined have been in 
Germany and England, where blue is the prevailing colour of 
the eyes. 
Division according to Sex.—Daltonism is much more common 
among men than women. I was told of a lady who confounds 
colours, but I have not had an opportunity of examining in what 
the defect of her sight consists. The same is the case with a 
sister of D* * *; two women mentioned by M. Seebeck*, and 
two cases cited by the English, but one of which is doubtful, 
are the only ones, in nearly 150 registered observations, which 
do not relate to the male sex. If it be true that the works of 
the needle are the means of perfecting a delicacy in the judge- 
ment of tints, and that in women the organ of colour is more 
developed than in men, as Gall asserts, it is worthy of remark, 
that these very works ought to lead daily to the detection of 
cases of daltonism in the female sex, if these cases were nu- 
merous. 
Influence of age and kindred.—Daltonism ordinarily dates 
from the birth. I know but two exceptions to the very great 
generality of this rule,——that of M. D * * *, to which I shall re- 
cur, and that of a young man of seventeen, mentioned by M. 
Seebeck {, who had suffered from an inflammation of the eyes 
from his infancy, and who had retained from this cause a weak- 
ness of sight ; but his daltonism can scarcely (schwerlich) be dated 
from that period. 
With respect to affinity, there are some daltonians no one of 
whose kindred exhibits this anomaly of vision; others have, so 
to speak, inherited it from their father or their uncle, either pa- 
ternal or maternal (without, in the latter case, the aunt partici- 
pating in it); lastly, it is not rare to find brothers, several of 
whom are daltonians, without their being all necessarily so. The 
sisters are almost always privileged, as we have seen. 
§ 2. Details of two Observations. 
The majority of my own observations approach too nearly to 
those which I have enumerated for it to be of use to give them 
* Mem. cited, p. 232. 
+ Phil. Trans., vol. Ixviii.; and Medico- Chirurg. Trans. of London, vol. ix. 
It is this last case which presents uncertainty. 
{ Mem. cited, p. 200. 
