MEDICO-LEGAL CONTRIBUTIONS ON ARSENIC. 
435 
increasing in force. Hail, rain^ and snow, fell at various 
places during its passage ; several of the churches upon which 
the lightning fell were set on fire; the wind was tempestuous, 
and the thunder-peals extremely loud. The barometer was 
strongly depressed, and the thermometer experienced con¬ 
siderable oscillations. M. Duprez, commenting on this 
alarming visitation, states that fourteen out of twenty-two 
cases of buildings being struck resulted in fires, and that the 
only edifice which was provided with a lightning-conductor 
suffered no damage. M. Quetelet adds that in his statistics 
of buildings or vessels struck by lightning, he found that 
out of a hundred and sixty-eight cases in which lightning- 
conductors had been struck, only twenty-seven, by reason of 
grave defects in their formation, had failed to exercise a pre¬ 
servative power. 
The average annual allowance of thunder-storms for Bel¬ 
gium is fifteen or sixteen, and they are twenty-one times 
more numerous in summer than in winter. The annual 
number for a particular locality will vary considerably, being 
four times as many in some years as in others, while fifteen or 
twenty leagues away the average has not been changed. In our 
northern countries winter storms, while the sun is below the 
equator, are usually formed between the clouds and the earth ; 
those in summer, when the sun is above the equator, are 
formed in a higher region, between the clouds and the sta¬ 
tionary layer of the atmosphere, and they have less tendency 
to strike elevated objects. Their region of action is often 
very limited, extending over only a few leagues. The velocity 
of the movement of thunder-storms equals that of the most 
rapid winds. 
MEDICO-LEGAL CONTRIBUTIONS ON ARSENIC. 
By Charles H. Porter, M.D., Professor of Chemistry and 
Medical Jurisprudence, Albany Medical College, 
(Continued from p* 173.) 
6. Remarks on the Method to he pursued ,—It is not difficult to 
identify the various metallic poisons, when they are free from 
other substances, by the application of a few simple tests. 
Where, however, the poisons are in admixture with organic 
matter, the problem presented is of far more difficult solution, 
for the organic substances may prevent, modify, or conceal, 
the characteristic chemical reactions which otherwise would 
