CYTOLOGY With Special Reference to the Metazoan Nucleus

For many years now it has been apparent to biologists that the nucleus- and especially its most conspicuous constituent the chromation - has special claims to be considered the master substance of the organism not only determining its form and activities within the life-time of each individual but by means of the gamete nuclei bringing about that organic continuity between parent and offspring which we call heredity. The absorbing interest of this conception has attracted many workers to the field of nuclear cytology and consequently the advance in knowledge and the output of hypotheses have been very great in recent years.