HYDROBROMIC ACID 341 



HYDROBROMIC ACID 

 ACIDTJM HYDROBROMICUM DILTJTUM. 



Diluted hydrobromic acid is an aqueous solution contain- 

 ing 10 per cent, by weight of hydrogen bromide (HBr). 

 Prepared by the distillation of potassium bromide with 

 concentrated phosphoric acid. A colourless, odourless acid 

 liquid. Specific gravity 1*077. It is occasionally employed 

 in human medicine as a nerve sedative, and it has been 

 recommended as an anodyne for nervous diseases of dogs in 

 doses of H\xx. to H\lx. (See Bromides.) 



CARBONIC ACID 



ACIDUM CARBONICUM. Carbon Dioxide. Carbonic Anhy- 

 dride. Choke Damp. After Damp. (C0 2 ). 



When air, containing more than ^^ parts by volume of 

 carbonic acid, is inhaled, by either man or the domestic 

 animals, discomfort and languor are produced. An atmo- 

 sphere containing T ^ promptly prevents removal of the car- 

 bonic acid from the blood, interferes with oxidation of the 

 tissues, and hence impairs their functions ; ^ shortly causes 

 unconsciousness and anaesthesia ; -J- does so more rapidly, 

 renders the blood markedly venous, but if respiration of the 

 mixture has been continued only for a few minutes, re- 

 covery gradually occurs on removal to the fresh air. 

 If the amount of oxygen is increased in the mixture 

 whilst the percentage of carbon dioxide remains the 

 same, asphyxia does not occur, but only narcosis from the 

 direct action of carbon dioxide in depressing the central 

 nervous system. Asphyxia, when it occurs, is referable to 

 the absence of, or decrease in, the amount of oxygen. Equal 

 parts of carbonic acid and air quickly produce death by 

 asphyxia, exhibiting the three stages characteristic of such 

 poisoning, namely (1) dyspnoaa, (2) convulsions, and (3) 

 paralysis. Examination after death discovers general 

 venous congestion, the blood dark-coloured, the right side 

 of the heart much distended with blood, the brain con- 

 gested, and sometimes exhibiting exudation and extravasa- 

 tion. In treating such cases, endeavour is made to oxygen- 



