SOME EFFECTS OF HOMOTYPIC EXTRACTS ON THE RATE OF CLEAVAGE OF ARBACIA EGGS

Abstract
1. Fertilized Arbacia eggs contain a readily extracted substance (or substances) which, inour tests, accelerated the rate of cleavage of such eggs to a statistically significant degree. 2. The acceleration produced by such an extract is not a result of the echinochrome it may contain nor of possible copper contamination. 3. The results are discussed against a background of population physiology, and the problems of over- and undercrowding of organisms.