contrary, we always find mixtures of these. So that, given quite similar compounds, e.g., several albumens, the cell has the power of making up mixtures of various kinds which give it a special stamp. By these means we see then that the possibilities for the production of specifically constructed kinds of cells are infinite. No one would be able to calculate the number that would account for all these possibilities.
We take it as probable, on the strength of numerous observations, that all through the animal kingdom similar organs show, besides their specific, and possibly individual characters, certain features which are common to all species of animals. All that is required is the recurrence of a particular albumen in the cell. We conjecture this from the fact that experiments have shown that certain ferments, when they act on albumen of a special kind, show specificity for the organ, but yet are not specific for any particular animal species. It is probable that we are here on the track of an important biological law.
Yet, in spite of these similar or kindred features, each species and individual retains, by means of the mixing of its cell components, the cell organization peculiar to its kind. If a single group be repeated but once only, the ferment that acts on it finds a point of attack. We lay stress on these points, because a casual consideration of the fact that in the
