to, the sulphuric dioxide takes up the water and the oxygen and becomes H2 SO4. Nitric acid gives off oxygen and becomes nitric oxide, this nitric oxide simultaneously takes up new oxygen from the atmosphere and is transformed into a higher oxide of nitrogen and from this acid sulphuric dioxide is again given off and made by the same process, so that, theoretically, an infinitely small amount of nitric acid should be effective to transform an unlimited quantity of sulphuric dioxide, oxygen and water into sulphuric acid. Change in matter regularly occurs through the passing of fluids through dead organic and inorganic membranes as in the artificial cells of Traube. It therefore appears that there is no progress by the way of organic change for the quality of organic change which was to explain life must itself be explained by life. We must therefore seek it elsewhere.
Life is a mode of existence of protoplasm and consists essentially in the constant renewal of the chemical constituents of this substance. Protoplasm is here understood in the modern chemical sense and comprises under this name all substances analogous to the white of an egg, otherwise called protein substances. The name is not satisfactory, for the ordinary white of egg plays the least active role of all transformed substances, since it only serves as mere nourishment for the yolk, for the self-developing germ. As long however as so little is known of the chemical constituents of protoplasm the name is better than any other because more inclusive.
Whenever we discover life we also find it bound up with protoplasm, and when we find a piece of protoplasm not in solution there we find also life, without exception. Doubtless the presence of other chemical constituents is necessary to a living body, to produce the various differentiations of these elements of life. They are not
