ed Government clerkships, and kept house together,
when one sickened and died of Bright's disease, and the other also
sickened of the same disease and died seven months later.

Both twins were apt to sicken at the same time in no less than nine
out of the thirty-five cases. Either their illnesses, to which I
refer, were non-contagious, or, if contagious, the twins caught them
simultaneously; they did not catch them the one from the other. This
implies so intimate a constitutional resemblance, that it is proper
to give some quotations in evidence. Thus, the father of two twins
says:--

"Their general health is closely alike; whenever one of them has an
illness, the other invariably has the same within a day or two, and
they usually recover in the same order. Such has been the case with
whooping-cough, chicken-pox, and measles; also with slight bilious
attacks, which they have successively. Latterly, they had a feverish
attack at the same time."

Another parent of twins says:--

"If anything ails one of them, identical symptoms _nearly always_
appear in the other; this has been singularly visible in two
instances during the last two months. Thus, when in London, one fell
ill with a violent attack of dysentery, and within twenty-four hours
the other had precisely the same symptoms."

A medical man writes of twins with whom he is well acquainted:--

"Whilst I knew them, for a period of two years, there was not the
slightest tendency towards a difference in body or mind; external
influences seemed powerless to produce any dissimilarity."

The mother of two other twins, after describing how they were ill
simultaneously up to the age of fifteen, adds, that they shed their
first milk-teeth within a few hours of each other.

Trousseau has a very remarkable case (in the chapter on Asthma) in
his important work _Clinique M. edicale_. (In the edition of 1873 it
is in vol. ii. p. 473.) It was quoted at length in the original
French, in Mr. Darwin's _Variation under Domestication_, vol. ii. p.
252. The following is a translation:--

"I attended twin brothers so extraordinarily alike, that it was
impossible for me to tell which was which, without seeing them side
by side. But their physical likeness extended still deeper, for they
had, so to speak, a yet more remarkable pathological resemblance.
Thus, one of them, whom I saw at the Neothermes at Paris, suffering
from rheumatic ophthalmia, said to me, 'At this instant my bro