Thornit has been manufactured by the same family for four generations. The powder was originally formulated by Mr W Watchman, a dedicated veterinary researcher and practitioner. 
 
Canker is caused by a mite, often picked up in grass. The more usual form is brownish waxy scabs inside the ears. These are made by the mite wishing to chew the ear in the dark. The scabs can be dry or weep slightly causing a smell. THe other form is much more offensive and stinks of gangrene whilst discharging globs of pus. In both cases the symptoms are scratching, head shaking, rubbing the ears on the floor and general distress. There can be red sores, inflammation and blood clots caused by constant scratching. The standard treatments of drops, steroids or antibiotics only give temporary relief and can have other side effects. There are no sterioids or antibiotics in Thornit, so it can be used perfectly safely. For all applications only a very small amount of thornit is needed. Care should be taken as iodoform can stain. For external use only and only to be administered as per these instructions. Keep sealed in a dry environment.
 
Can also be used not only in ears but on the body, anus and paws:
 
Body - The mite can transfer itself from the ears to the scurf of the body and can cause intense distress in cats and dogs by constantly moving, scratching and biting all parts of the animal. It is minute and very mobile. Dust Thornit lightly onto the skin. If the animal has long hair part the hair with a comb dusting a little thornit on the exposed skin. A little powder will go a long way.
 
Anus - If the animal pulls its bottom on the floor and the problem is not anal glad trouble, the mites could have made a breeding bed under the tail. Apply a tiny amount of unperfumed moisturising lotion to a gloved finger and dip into Thornit Powder and apply just below the tail where necessary.
 
Paws - Mites can get between the claws, making the animal first lick the paw constantly which can turn the pads soft, then tear out the hair and finally even nibble a hole in themselves. Hold the paw in a plastic bag containing a small amount of Thornit and work the powder between the claws, into the pads and a little way up the leg.