A Fruit-setting Hormone from Apple Seeds

IN the apple, fruit size and shape are known to be closely correlated with the number and position of the fertile seeds, an observation which suggests that the developing seed may be the source of a hormone which initiates and controls the growth of the fruit. Experimental evidence supporting this has recently been obtained for the apple variety Crawley Beauty, from the young seeds of which it has been found possible to prepare extracts which are active in stimulating the development of unfertilized tomato ovaries.