MINEEAL OE INOEGANIC POISONS 69 



irritant than by reason of its indirect nervous effects. 

 Chromates of lead and of barium are yellow paints very 

 commonly used, and large quantities of chromate are used 

 in the chrome tanning process for leather. 



Toxic Dose. — That for the horse is given by Kaufmann 

 as 450 grains, for the dog 45 to 60 grains, but according 

 to a foreign abstract* 300 grains proved fatal to a 

 horse. 



Effects. — Chromates are never given internally, but are 

 absorbed through wounds or through the skin, producing 

 dyspnoea, general lowering of the temperature, acceleration 

 of the pulse, convulsive movements, followed by weakness, 

 insensibility, and death. In the case referred to above, 

 300 grains of potassium bichromate were given to the horse 

 in the morning in mistake for sodium bicarbonate. In 

 view of the fact that bichromate is orange and bicarbonate 

 colourless, this seems a most extraordinary mistake, unless, 

 indeed, the bicarbonate had been coloured by a yellow dye. 



There was no appetite in the evening, and on the next 

 day there were observed stiffness, frequent pulse, heart 

 excited and irregular, temperature 101^° F., respiration 

 slow, mucous membranes cyanotic, abdomen painful, in- 

 tense thirst. Later the breathing became hurried and 

 short, the temperature rose to 102-7° F., and the stiffness 

 passed off ; but in spite of treatment the animal died forty 

 hours after ingestion of the poison. 



Post-Mortem Appearances. — On post-mortem the con- 

 junctival membranes were found to be covered with hsemor- 

 rhagic spots, the buccal membranes having small, shallow 

 ulcers ; the mucous membranes of the stomach showed 

 numerous blackish spots, the small intestines were covered 

 with a diphtheritic layer and contained a blood-coloured 

 fluid, as also did the large intestines ; the membranes of the 

 lungs, heart, kidneys, bladder, and spleen were destroyed. 



Chemical Diagnosis. — The chemical diagnosis is not 

 difficult. In the above-mentioned case no potassium bichro- 

 mate was found in the intestinal fluid, but it must be 

 * Vet. Becord, 1906, p. 290. 



