SCIENTIFIC SUMMAET. 
103 
Microscopic Examination of Secretions . — The value of the microscope as a 
substitute for the test-tube iu the qualitative analysis of secretions, such as 
urine, has been very well illustrated in a paper read at the late Pharma- 
ceutical Congress, by Mr. Stoddart. This gentleman endeavoured to show 
that a mere chemical examination of a substance was of little value, since 
it gave no indication of how the several constituent elements were com- 
bined. He gave an illustration of the value of the microscope to the 
chemist, by showing that in the examination of animal secretions no less 
than seven different substances could be detected in a few minutes, by 
applying the tests to a drop of the secretion placed under the microscope, 
and watching and noting the form of the crystals then formed. 
A Galvanic Probe-indicator., which would be found useful in searching for 
bullets in gun-shot wounds, has been lately described by an American 
surgeon. It consists of a pair of forceps whose limbs are electrically isolated, 
and are in connection with the wires of a battery. It is employed in gun- 
shot wounds in searching for the ball. If it touches a ball the isolation is 
broken, and a current being formed, a small bell in connection with the 
battery is caused to ring. The idea is an admirable one theoretically ; it 
only remains to be seen whether the tissues themselves, in the absence of a 
ball, may not be sufficient to complete the current, and thus give an indi- 
cation of the presence of a ball where no ball existed. It was first de- 
scribed in England in the London Review of Nov. 30, and it elicited a letter 
from Mr. He Wilde the engineer, who claims the merit of originating this 
instrument some years ago. — Vide Ijondon Review., Oct. 7. 
Physiological Action of Calabar-bean . — We have received from Dr. Eraser, 
of Edinburgh, a copy of this fine memoir upon the action of the ordeal-bean. 
This essay, which is reprinted from The Transactions of the Royal Society 
of Edinburgh, is thoroughly exhaustive in its treatment of the subject, 
and is, we should say, the most elaborate monograph upon a single poison 
yet published. Dr. Fraser records the results of a multitude of experiments 
made to determine the action of this substance on the various organs of 
the body, but that part which relates to the influence of physostigmine on 
the iris is especially important. With regard to the relative effects of 
atropine and physostigmine. Dr. Fraser says that the changes in the iris 
appear to require the co-operation of special radiating and circular muscular 
fibres, with a system of contractile blood-vessels possessing to a certain ex- 
tent the properties of erectile tissue. A mere antagonism between the two 
muscular apparatus could not, he thinks, alone account for the effects of 
either atropine or physostigmine. All the muscular fibres in the iris are 
unstriped, and physostigmine relaxes, while atropia contracts such fibres. 
Experiments on the Cause of Scurvy . — M. Prussak, of St. Petersburgh, 
has published an account of some experiments, which go far to demonstrate 
the relation between scurvy and the presence in the blood of an excess of 
common salt. M. Prussak placed the web of a frog’s foot under the mi- 
croscope, so as to observe the passage of the blood through the smallest 
blood-vessels. He then injected a solution of salt beneath the frog’s skin, 
and watched the effect on the vessels. He perceived that the blood cor- 
puscles distended the vessels, and gave rise to the patches of dark-coloured 
extravasations, extremely like the peculiar livid blotches seen on the skin of 
