OXALIC ACID. 
§§ 723= 724-] 
545 
followed. Emil Pfeiffer 1 gave a dog in three successive days -2, *5, and 
lastly 1 grm. oxalic acid with meat, but no symptoms resulted. Yet 
that oxalic acid, as sodic oxalate, is poisonous to dogs, if it once gets 
into the circulation, cannot be disputed. The accepted explanation is 
that the large amount of lime phosphates in the digestive canal of dogs 
is decomposed by oxalic acid, and the harmless lime oxalate formed. 
Oxalic acid is absorbed into the blood, and leeches have been known 
to die after their application to a person who had taken a large dose. 
Thus Christison 2 quotes a case related by Dr Arrowsmith, in which this 
occurred :—“ They were healthy, and fastened immediately ; on looking 
at them a few minutes after, I remarked that thev did not seem to fill, 
and on touching one it felt hard, and instantly fell off motionless and 
dead ; the others were in the same state. They had all bitten, and 
the marks were conspicuous, but they had drawn scarcely any blood. 
They were applied about six hours after the acid had been taken.” 
§ 723. Effects of Vaporised Oxalic Acid. —Eulenberg has experi¬ 
mented on pigeons on the action of oxalic acid when breathed. In one 
of his experiments, -75 grm. of the acid was volatilised into a glass 
shade in which a pigeon had been placed ; after this had been done five 
times in two minutes, there were uneasiness, shaking of the head, and 
cough, with increased mucous secretion of the nasal membrane. On 
continuing the transmission of the vapour, after eight minutes there 
were again restlessness, shaking of the head, and cough ; after eleven 
minutes the bird fell and was convulsed. On discontinuing the sub¬ 
limation, it got up and moved freely, but showed respiratory irritation. 
On the second day after the experiment, it was observed that the bird’s 
note was hoarse, on the fourth day there was slowness of the heart’s 
action and refusal of food, and on the sixth day the bird was found dead. 
Examination after death showed slight injection of the cerebral mem¬ 
branes ; the cellular tissue in the neighbourhood of the trachea contained 
in certain places extravasations of blood, varying from the size of a pea 
to that of a penny ; the mucous membrane of the larynx and trachea 
was swollen and covered with a thick croupous layer ; the lungs were 
partially hepatised, and the pleura thickened ; the crop as well as the 
true intestines still contained some food. 3 
§ 724. The Effects of Oxalic Acid and Hydropotassic Oxalate on 
Man. —The cases of oxalic poisoning have been invariably due to either 
oxalic acid or hydropotassic oxalate, the neutral sodic or potassic oxalates 
having hitherto in no instance been taken. The symptoms, and even 
the locally destructive action of oxalic acid and the acid oxalate, are so 
similar that neither from clinical nor post-mortem signs could they be 
differentiated by anyone not having a previous knowledge of the case. 
1 Archiv der Pharm. (3 R.), xiii. 544, 1878. 
2 Treatise on Poisons. 8 Gewerbe Hygiene, p. 423. 
35 
