Chemistry gives us a number of examples of variations in the reaction of substances which with the same composition differ in the molecular arrangement.

Even in so simple a mechanism as a watch there are slight differences in structure which gives to each watch certain individual characteristics, but the type as an instrument constructed for recording time remains.

In the fusion of the chromosomes of the male and female sexual cells, to which the hereditary transmission of the ancestral qualities to the new offspring is due, there are differences in the qualities of each, for the individuality of the parents is expressed in the germ cells, and the varying way in which these may fuse gives to the new cell qualities of its own in addition to qualities which come from each ancestor, and from remote ancestors through these.

The qualities with which the new organism starts are those which it has received from its ancestors plus its individuality.

The fact that the sexual cells are formed from the early formed cells of the new organism which represent all of the qualities of the fertilized ovum or primordial cell, renders it unlikely that the new offspring will contain qualities which the parents have acquired.