So much we may say at once: The significance of amphimixis cannot be that of making multiplication possible, for multiplication may be effected without amphimixis in the most diverse ways--by division of the organism into two or more, by budding, and even by the production of unicellular germs. Even though these last are usually in various ways so organized that they must undergo amphimixis before they can develop into new organisms, yet there are numerous germ-cells which are not subject to this condition (e.g. spores), and there are--as we have seen--many germ-cells, adapted for amphimixis, which always, or in certain generations, or even only occasionally, emancipate themselves from this condition under certain external influences: I refer to egg-cells which develop parthenogenetically. If amphimixis is not a universal preliminary condition of reproduction, wherein lies the necessity for its general occurrence among living organisms? We have already learned that there are two results produced without exception by amphimixis; one of these is the antecedent reduction of the original number of ids by one half, and the consequent new combination of ids which results from this; the other is the union of two such halved germ-plasms from two different individuals. The first we may, with Hartog, compare to the removal of half of a pack of cards previously mixed, the second to the combination of two such halves from different packs. The first process brings nothing new into the complex of primary constituents, but rather removes a part--larger or smaller--of its characters: not necessarily exactly half of these, since each individual kind of id may be represented by doubles or multiples. But the reduction simplifies the composition of the germ-plasm, and might by itself, through the struggle of the ids in ontogeny, lead to a resultant different from the parent, that is, to a new individuality. Through the second process, however, new individual traits are of necessity added, and make the resultants still more markedly diverse, that is, if the ids of both parents attain to expression in the struggle of ontogeny, and this, as we have already seen, is usually the case, though not always and certainly not always in all parts. Thus amphimixis, together with the preparatory reduction of the ids, secures the constant recurrence of individual peculiarities through the ceaseless new combinations of individual characters already existing in the species.