grattage

The scraping away of granulations (from an ulcer etc.) in order to stimulate healing.

August 18th.—Operation by "grattage" without ether. The pain experienced by the patient was quite severe.

Among those vaccinated by piqûre (sticking) a very small number only contracted the disease, and in these it was mild, while in those vaccinated by grattage it was, in general, severe.

A technique popularized by Max Ernst involving scraping at dried paint in order to form patterns.

Automatism in art can arise quite deliberately from manual techniques (such as frottage, grattage and decalcomania in the visual arts, algorithmic or statistical procedures in musical composition, or random verbal collages in poetry) or accidentally from altered states of consciousness (for example, intoxication, hallucination, trance and ecstasy).

These same forest images appeared when he adapted his frottage technique to the roughly rubbed and scratched painting techniques of grattage.