322 
ARSENIC IN PAPER-HANGINGS. 
such cases is not to be tested by the degree in which 
workmen escape or are able to resist the effects of noxious 
manufactures. 
In reference to Mr. Campbell’s negative experiment, it 
practically establishes nothing with respect to the question at 
issue. Dr. Halley’s room exposed a surface of 6l6 square 
feet of arsenical paper. In one square inch of the paper I 
found more arsenic than I have frequently found in the whole 
liver of a person who has died from that poison. Dr. Halley 
sat in the room for five or six hours at a time* Some symp- 
toms appeared in a few days. They were confirmed in three 
weeks by threatened paralysis. Mr. Campbell’s experiments, 
on the other hand, merely show that a quantity of air (the 
quantity not specified), blown by a bellows for one hour , 
through a tube, heated from 60° to 140° over strips of 
arsenical paper, exposing in a close bottle a surface of one 
square foot only, did not give any "trace of arsenic in a solution 
of potash placed to receive it ! This result is not inconsis- 
tent with the view, that the symptoms of Dr. Halley and 
others proceeded from the arsenical paper-hangings. A per* 
ceptible quantity of arsenious acid, if obtained in one hour 
from one square foot of paper, would render a room, ex- 
posing six hundred square feet, in a few days Gr weeks a 
complete chamber of death to all who entered it. A similar 
experiment might be adduced, to show, contrary to well- 
known facts, that no person can be poisoned by lead, as a 
result of the emanations from fresh paint! When a scientific 
experiment does not fairly include all the conditions which it 
is intended to illustrate, it is worse than useless ; for it not 
only misleads those who do not perceive its irrelevancy, but, 
in a sanitary point of view, it may be the means of perpe- 
tuating a serious evil. It is undoubtedly desirable to collect 
further evidence on this matter; but in my opinion there is 
enough already collected, to show that those who have their 
walls covered with a poisonous powder must be prepared to 
encounter a certain amount of risk. The manufacturers of 
the arsenical papers profess to guarantee immunity ; but 
what will follow if they should be mistaken, and if it should 
in the end turn out that the interests associated with their 
trade and means of living had clouded their judgment ? The 
Prussian Government have had this subject duly inquired 
into, and the result of the inquiry has been the following 
regulation, which is in force in Prussia : 
“ Green copper colours containing arsenic are not allowed 
to be sold as water or oil colours, for painting in-door work 
or printing paper-hangings . If found on the premises of 
