Albinism and Variegation are apparently due to causes totally different from any yet mentioned. Church's analyses have shown that albino leaves contain more water and less organic matter than green ones of the same plants, but not necessarily less ash constitutents. The composition of the ash points to there being more potash and less lime in the white organs than in the green ones, and, speaking generally, the former are related to the latter much as young leaves are related to mature ones.

The whole matter is complicated by the behaviour of certain variegated plants - e.g. Ribbon grass, Calla, Abutilon, which are usually regarded as partial albinos.

Meyen showed long ago that such variegated plants, if grafted on green ones, may induce the development of variegated leaves on both scion and stock, and Morren and others have not only confirmed this but have also shown that variegation may be inherited through the seed. Nevertheless some care has to be taken with many of these variegations lest rich soil, bright light, and other favourable treatment favour the restitution of the green colour. These facts may be interpreted in various ways. Some disturbance of physiological functions of the roots, due to unfavourable conditions of soil, may be the cause; but Beijerinck has lately published some results which show that some of these albino diseases can be induced by inoculating normal plants with the juice of spotted ones even though such juice has been filtered through porcelain, and concludes that a "contagium fluidum vivum" of the nature of a transmissible enyzme is the agent which disturbs the physiology of the infected cells.

Koning, while confirming these results in the main, refers them to a micro-organism so small that it traverses the porcelain filter.