568 POISONS : THEIR EFFECTS AND DETECTION. [§ 747 ' 
on pigeons, the birds were secured under glass shades, and exposed to 
the vapour of metallic arsenic vaporised by heat. It is scarcely neces¬ 
sary to remark that in operating in this way the poisoning was not 
by metallic arsenic vapour, but by that of arsenious acid. One of these 
experiments may be cited :—A pigeon was made to breathe an atmo¬ 
sphere charged with vapour from the volatilisation of metallic arsenic. 
The bird was immediately restless ; in thirty minutes it vomited 
repeatedly, and the nasal apertures were noticed to be moist; after a 
little while, the bird, still breathing the arsenious acid atmosphere, was 
much distressed, shook its head repeatedly, and yawned ; in fifty minutes 
the respiration was laboured, and in fifty-nine minutes there was much 
vomiting. On removing the bird, after it had been exposed an hour to 
the vapour (-16 grm. of metallic arsenic having been evaporated in all), 
it rapidly recovered. 
Six days after, the pigeon was again exposed in the same way to the 
vapour, but this time *56 grm. of metallic arsenic was volatilised. In 
fifteen minutes there was retching, following by vomiting. On taking it 
out after an hour, it remained very quiet, ate nothing, and often puffed 
itself out ; the breathing was normal, movements free, but it had 
unusual thirst. On the second and third day the excretions were 
frequent and fluid ; the cardiac pulsations were slowed, and the bird was 
disinclined to move. On the fourth day it continued in one place, 
puffing itself out ; towards evening the respirations slowed, the beak 
gaping at every inspiration. On attempting flight, the wings fluttered 
and the bird fell on its head. After this it lay on its side, with slow, 
laboured respiration, the heart-beats scarcely to be felt, and death took 
place without convulsions, and very quietly. On examining the organs 
after death, the brain and spinal cord were very bloodless ; there were 
ecchymoses in the lungs, but little else characteristic. The experiment 
quoted has a direct bearing upon the breathing of arsenical dust ; as, for 
example, that which floats in the air of a room papered with an easily 
detached arsenical pigment. Other experiments on birds generally have 
shown that the symptoms produced by arsenious acid in solution, or in 
the solid form, in a dose insufficient to destroy life, are languor, loss of 
appetite, and the voidance of large quantities of liquid excreta like 
verdigris. With fatal doses, the bird remains quiet ; there are fluid, 
sometimes bloody, excretions ; spasmodic movements of the pharynx, 
anti-peristaltic contraction of the oesophagus, vomiting, general tremb¬ 
ling of the body, thirst, erection of the feathers, and laboured respiration. 
The bird becomes very feeble, and the scene mostly closes with in¬ 
sensibility and convulsions. 
Mammals, such as cafes, dogs, etc., suffer from symptoms fairly iden¬ 
tical with those observed in man ; but the nervous symptoms (according 
to P. Hugo) do not predominate, while with rabbits and guinea-pigs 
