7 26 POISONS : THEIR EFFECTS AND DETECTION. [§§ 942 - 944 . 
* 
the moment of introduction of the salt, the other when the substance 
has been exposed for some time to a high temperature. This is caused 
by a rapid loss of chlorine, so that the first spectrum is due to BaCl 2 , 
with a variable mixture of BaCl, the second to BaCl alone. 
§ 942. Baric Carbonate, BaC0 3 =197—specific gravity, 4*3; BaO, 
77-69 per cent. ; C0 2 , 22-31—in its native form termed Witherite, is a 
dense, heavy powder, insoluble in pure water, but dissolving in acetic, 
nitric, and hydrochloric acids, the solution giving the reactions of 
barium. 
A rat-poison may be met with composed of baric carbonate, sugar, 
and oatmeal, flavoured with a little oil of aniseed and caraway. 
§ 943. Sulphate of Barium, BaS0 4 —specific gravity, 4-59; BaO, 
65-66 per cent. ; S0 3 , 34-34 per cent.—is a pure white powder when 
recently precipitated, absolutely insoluble in water, and practically 
insoluble in cold dilute acids. It is quite unalterable in the air at a 
red heat ; on ignition with charcoal it may be converted almost entirely 
into sulphide of barium, and by ignition with CaCl 2 into chloride. 
§ 944. Effects of the Soluble Salts of Barium on Animals. —One 
of the early notices of the poisonous characters of barium compounds 
was by James Watt, 1 who found that Witherite, given to dogs, produced 
vomiting, diarrhoea, and death in a few hours. Sir Benj. Brodie 2 
administered barium chloride, and noticed its paralysing effect on the 
heart. Orfila 3 made several experiments, and observed that 4 grins, of 
the carbonate produced death in dogs in periods varying from one to 
five hours ; but in these experiments the gullet was tied. The later 
investigators have been Ganelin, Onsum, Cyon, and Bohm. 4 Gmelin 
found barium carbonate and barium chloride act in a very similar 
manner ; and, indeed, it is improbable that barium carbonate, as 
carbonate, has any action, but, when swallowed, the hydrochloric and 
other acids of the stomach form with it soluble compounds. J. Onsum 
made eight experiments with both barium carbonate and chloride on 
animals. The respiration was quickened and, at the same time, made 
weak and shallow ; the heart’s action was accelerated ; the animals 
became restless ; and there was great muscular prostration, with para¬ 
lytic symptoms ; convulsions did not occur in any one of the eight 
animals. He found, on post-mortem examination, the right side of the 
heart full of blood from backward engorgement ; he describes a plugging 
of the small arteries with little fibrinous coagula, having an inorganic 
1 Memoirs of the Literary and Philosophical Society of Manchester, vol. iii. p. 609, 
1790. 
2 Phil. Trans., 1812. 3 Traite des Poisons, 3rd ed., t. i., Paris, 1826. 
4 Gmelin, C. G., Versuche iiber die Wirkungen des Baryts, Strontians, Chroms, 
Molybddns, Wolframs, Tellurs u.s.w. auf den thierischen Organismus, Tubingen, 
1824 ; Onsum, J., Virchow’s Archiv, Bd. ii.,- 1863 ; Cyon, M., Archiv f. Anatomie, 
Physiologie, etc,, 1866 ; Bohm, Archiv f. experiment. Pathol., Bd. iii., 1874. 
