The tendency to individuation cannot be more strongly marked than in the simple experiment of vaccination: we insert a small particle of the so-called vaccine lymph under the skin, and by this means we multiply to an enormous extent, the power which, in the first instance, we had in the form of minute corpuscles in a dry and apparently inert state; nevertheless, though in this condition there must have existed the tendency to individuation or multiplication of individual existence, and the germs are here to their active existence, as seen in the development of the vaccine vesicle, what the egg is to the bird,[7] as described above; we may, therefore, say that the power which exhibits itself in the production of a vaccine vesicle, must have been latent in the dried matter. It is the opinion of Muller that the entire vital principle of the egg {25} resides in the germinal disk alone, and since _the external influences which act on the germs_ of the most different organic beings are the same, we must regard the simple germinal disk, consisting of granular amorphous matter, as the potential whole of the future animal, endowed with the essential and specific force or principle of the future being, and capable of increasing the very small amount of this specific force and matter, which it already possesses, by the assimilation of new matter. After speaking of inanimate objects, Dr. Carpenter says; "and what compared with the permanence of these is the duration of any structure subject to the conditions of _vitality_? _To be born_, to grow, to arrive at maturity, to decline, to die, to decay, is the sum of the history of every being that lives; from man, in the pomp of royalty, or the pride of philosophy, to the gay and thoughtless insect that glitters for a few hours in the sunbeam and is seen no more; from the stately oak, the monarch of the forest through successive centuries, to the humble fungus which shoots forth and withers in a day."