KILLS BY CARDIAC OB RESPIRATORY ARREST 431 



and paralysis of voluntary muscles supervene, and death 

 from paralysis of the cardiac or respiratory centre. Unlike 

 other acids, prussic acid does not coagulate albumin or 

 break down the formed elements of the blood. The potas- 

 sium and other cyanides are soluble, readily yield their 

 cyanogen, and are active poisons, though less so than the 

 free acid ; but the ferro-cyanides and other double cyanides 

 are greatly less active and non-toxic. 



Toxic ACTIONS. Horses have been poisoned in one or two 

 minutes by ten to twenty minims of anhydrous acid, in- 

 jected hypodermically. Trousseaux and Pidoux placed a 

 piece of cotton wool, on which six minims of anhydrous acid 

 had been dropped, in the nostrils of two horses. In ten 

 seconds they dropped as if dead, and continued for an hour 

 to exhibit grave nervous symptoms convulsions, spasms, 

 vertigo, paralysis, and stupor. Horses swallowing four to 

 five drachms of the two per cent, medicinal acid may die 

 within an hour. Coleman gave an aged horse repeatedly, 

 at intervals of several days, one to three drachms of acid, 

 containing about four per cent, of anhydrous acid, and noted 

 much excitement, the pulse raised to 100, and in one experi- 

 ment to 160, laboured breathing and tetanic contraction of 

 the muscles ; but the effects gradually passed away. Six 

 ounces of medicinal acid given to an old elephant caused 

 only slightly laboured breathing. The horse can be quickly 

 killed by intrathoracic injection of one or two drachms of 

 Scheele's acid. 



Dogs, cats, and rabbits, which had one to four drops of 

 anhydrous acid placed on the tongue or within the eyelids, 

 in ten to thirty seconds made three or four hurried inspira- 

 tions, a convulsive expiration, often a cry, had tetanic con- 

 vulsions, and died in one to three minutes. Air saturated 

 with the gas killed one dog in ten seconds, another in five, 

 and a cat in two seconds. Guinea-pigs inhaling it for one 

 second die in fifteen seconds. Strong rabbits inhaling it for 

 three seconds die in thirty seconds ; but birds are not 

 susceptible, and frogs are still less so. Dogs and cats 

 receiving forty to sixty minims of the two per cent, acid were 

 sometimes poisoned almost as rapidly as with the anhydrous. 

 More frequently, however, life is prolonged for several 



