Can't help with chemical poisonings, but I have a story someone with a dog might find interesting!
When Arjun ws a puppy, six months old, he started to go lame. At first it was justa dragging of the hind legs, but it got worse andworse very quichly. The vet had no idea what was wrong. Two days later he could hardly move his legs; when he tried to walk, he stumbled and fell over. We went to another vet, had x-rays taken, no explanation. We took him to a dog hospital. By this time he could not walk. He just lay there, almost as if paralysed. They couldn't figure out waht was wrong. They wanted to do some expensive procedure which involved removing bone marrow just in order to test it, and dig into his brain or something - mind you, it wasn't a treatment, just some kind of very complicated procedure to see if he had a neuological problem. I can't remember what the vet said at the time - it was very technical, and only one thing was clear - they had no idea what was wrong. We felt it was all ********.
We took him home and refused the diagnostic procedure. We were advised to put him to sleep, but as he didn't seem to be in pain, we didn't. It was my daughter's beloved dog; she was ten at the time.
By this time he couldn't even eat. He lay on the carpet and we fed him liquids through a syringe. He couldn't even lift his head. But you could tell he wasn't in pain by the eyes, which were freindly and puzzled, but not fearful or in anguish. He seemed to be dying.
Every morning I woke up and expected to find him dead. But I would go into the sitting room and the first thing I'd hear was "thump, thump, thump" - his tail wagging, and hitting the floor. He still couldn't lift his head, but was taking in the liquids. I prepared my daughter for his death as well as I could.
We were supposed to al be going to India, but my husband opted to stay behind to look after Arjun, who still couldn't move. Days later, there was no change - just the tail wagging.
On Christmas day, we were sitting on a hill an dmy dughtre prayed with all her heart for him. She told God, if it was possible, to heal him, but if not, let him die and look after his soul.
We called my husband that evening and he said Arjun was eating again. the next day, he was stuggling to get up. A day later, he was walking. A week later, he was back to normal.
When we returned to Germany, my husband had researched the whole thing and found the answer:
Arjun was at that phase where he chewed everything up. The week before he took ill, he had dug up all my husband's potted plants in the basement and ripped them apart.
Among the destoyed plants was cycamen; my husband found out that the roots of cyclamen are poisonous, and the symptoms are exactly those the dog showed. He actually should have died.