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11 in the body are not transmitted for this germ-plasm occupies a sphere of its own and is uninfluenced by any environmental and functional changes which may appear in the some. The some merely serves for the lodgement and nutrition of the germ-plasm. Thus the relation of each individual to the inherited characters is merely that of a trustee. It hands on to the next generation what he received from the previous one and this germinatal material is totally unaffected by any habits which he may have formed or any changes which his body may have undergone due to the action of external circumstances.

Weismann's theory of the continuity of the germ-plasm has been accepted by many on account of its simplicity. But this in itself is no justification for the acceptance of any theory. The theory must be tested by observation and experiment. As regards variation, he admits that in the case of unicellular organisms changes have been brought about by the environment. In fact so far as the Protozoa are concerned he is a strict Lamarckian. But all variations among the Meta-zoa are ascribed to different sources. He traces them to the commingling of the qualities of the germ—plasm of the two parents which occur in fertilisation. To him this is the chief function of propagation and he speaks of it as. He has also referred to another possible source of variation - the reducing division which takes place prior to fertilization in the mat of the ovum, or in the course of spermato-genesis.