54 
MISCELLANEA. 
in cases where this could be accomplished readily in ordinary 
states of the pupil, so that most persons complain of it 
bitterly. In cases of amblyopia, also, the patient becomes 
usually less able to distinguish objects during several days; 
and shows unnecessary alarm lest the instillation should 
have injured the sight permanently, notwithstanding the 
forewarning, which I have never neglected, that the effect 
was merely of a temporary nature. 
The objection, thus occasioned, led me to the inquiry, 
whether it was not possible to fulfil our purpose, without 
exposing the patient to the inconvenience of which he thus 
justly complains. One obvious course was, to employ 
weaker solutions ; and yet I continued for long, like others 
(it may be said in excuse), to pursue the old routine, and to 
use in all cases the solution of gr. iv. to the ounce of water. 
Dr. .De Ruiter (‘ Nederlandsch Lancet/ 1854, p. 464) had 
already stated, that a drop of a solution, in which was con- 
tained not more than TTS^BW of sulphate of atropine, when 
kept some time in contact with the eye of a dog, sufficed to 
produce a dilatation lasting for twenty hours. Farther 
experiments on dogs, have shown him that a solution with 
a proportion of of sulphate of atropine, induces 
powerful dilatation in ten to fifteen minutes, which disappears 
only at the end of four days ; that a solution with 2 ~r,J o o> ^ ve 
to ten minutes in contact with the eye, causes also strong 
dilatation, and even sometimes immovability; that a solution 
with tt^.Vooj kept five minutes in contact, gave a good 
dilatation at the end of an hour, which lasted eighteen 
hours; that with a threefold dilution, and the same time 
of application, a perceptible dilatation still followed, and 
that it w T as only upon a sixfold dilution, and therefore 
with TT 2 ,W^ that the effect became doubtful. The sensitive- 
ness of the eye to atropine, indeed, excites astonishment, 
when w T e consider that of the single drop of the attenuated 
solution, which suffices to produce dilatation, probably not a 
fiftieth part is absorbed . — Monthly Journal of Medical Science . 
NATURAL DEPOSIT OF SxVLTPETRE. 
Professor W. H. Eilet, of the United States, reports that 
there has been discovered in Bradford county, Pennsylvania, 
a regular vein of Nitre, believed to be unique in its character. 
The nitre occurs as a solid and uncrystalline deposit in the 
horizontal seams of a sandstone rock, and in veins proceeding 
