The sheep's brain presumably acted as a gloss enhancer, not as an adhesive, for on the one hand it does not have adhesive properties, and on the other, a sheep's brain is only the size of a hen's egg, so the quantity would be insufficient.
羊腦在這兒扮演的角色，應為光澤助劑而非接著劑，一則它沒有接著的效果，再來，一個羊腦約略與雞蛋一般大小，不足以應付接著劑的用量。