320 
ARSENIC IN PAPER-HANGINGS. 
tion of the fine impalpable dust was a continual source of 
lead-poisoning* It was not mere contact by the skin, for it 
was observed in the French factories that horses* dogs* and 
rats suffered from this form of poisoning; A sunbeam 
cannot strike across a room without revealing myriads of 
floating particles in the atmosphere* that are commonly in- 
visible to us, but which are always contained in the air that 
we breathe. Are we to be told that this dust can, under no 
circumstances, be derived from the green pigment on the 
walls of a room, or that it can be safely breathed by every 
human being, because some of the workmen in colour- 
factories do not suffer from the effects ? I object to these 
assumptions as wholly improbable. 
That arsenic was the cause of the symptoms in Dr. 
Halley’s case, appears to be established by the fact, that they 
disappeared on the removal of the arsenical paper and the 
substitution of one not arsenical. We have here as close 
a connexion of cause and effect as we can reasonably expect 
to find. 
Dr. Halley, who can have rlo motive but that arising from 
a desire for scientific truth* states that he has substituted a 
plain wainscot oak paper ; that he has since regularly used 
the room— the conditions of which, in other respects, re^ 
mained the same— without experiencing any of the ill effects 
so Constant before ; and that he has recovered his health. If, 
as it is suggested in Mr. Paul’s paper, the burning of gas 
had been the cause of the symptoms, how are we to 
explain the recovery of Dr. Halley, when the only change 
that he makes is the stripping off the paper from the 
walls ? 
It is said these cases are few, and ought to be very 
numerous, if really caused by the arsenical papers now so 
commonly used in dwellings* I would add, they ought to 
be still more numerous if caused by the burning of gas. The 
effects produced by the arsenical papers may, however, be 
influenced by various circumstances — ‘the size of the room — 
the amount of ventilation — -the time during which it is 
inhabited— and the special susceptibility of the person. 
Lastly, how many cases of illness, probably arising from this 
hitherto unsuspected cause, may have been overlooked or set 
down to other causes. In reference to the action of lead, the 
same apparent difficulties present themselves. One man is 
affected with lead-paralysis and other symptoms of poisoning 
simply from handling pewter pots : another may handle lead 
for life in his trade as a plumber, without suffering from any 
symptoms of poisoning. In an establishment consuming the 
