PEOTOPLASM 35 of diverse stratifications and combinations. The chemistry of to-day, with its imperfect methods of investigation, is totally powerless before these intricate organic compounds, and it is possible only to surmise, from the infinitely varied physiological qualities of the number- less kinds of plastids, the infinite variety of plastidules out of which they are composed. According to the plastid theory recently advanced, the great variety of vital phenom- ena is the consequence of the infinitely deli- cate chemical difference in the composition of protoplasm, and it considers protoplasm to be the sole active life substance. This theory puts force and matter in living organisms into the same causal connection which has long been accepted for force and matter in inor- ganic bodies. This conception has been rap- idly matured, especially in the past 20 years, through the more exact information obtained in regard to the lowest kinds of organisms. Yet the idea had been grasped more than half a century ago ; for the " primordial slime " which Lorenz Oken proclaimed in 1809 to be the original source of life, and the material basis of all living bodies, possessed in all es- sentials the same qualities and the same im- portance now ascribed to protoplasm ; and the sarcode so called, which in 1835 was pointed out by the French zoologist F61ix Dujardin as the only living substance in the body of rhizo- pods and other inferior primitive animals, is identical with protoplasm. But when Schlei- den and Schwann, in 1838, developed their cell theory, they were not acquainted with the fun- damental significance of protoplasm. Even Hugo Mohl, who in 1846 was the first to apply the name protoplasm to the peculiar serous and mobile substance in the interior of vege- table cells, and who perceived its high impor- tance, was very far from understanding its significance in relation to all organisms. Not until Ferdinand Cohn (1850), and more fully Franz linger (1855), had established the iden- tity of the animate and contractile protoplasm in vegetable cells and the sarcode of the lower animals, could Max Schultze in 1858-'61 elabo- rate this protoplasm theory of the sarcode, so as to proclaim protoplasm to be the most essential and important constituent of all or- ganic cells, and to show that the bag or husk of the cell, the cellular membrane, and the in- tercellular substances, are but secondary parts of the cell, and are frequently wanting. In a similar manner Lionel Beale (1862) distin- guished such primary forming and secondary formed substances in all organic tissues, and gave to protoplasm, including the cellular germ, the name of " germinal matter," and to all the other substances entering into the com- position of tissues, being secondary and pro- duced, the name of "formed matter." The protoplasm theory received a wide and thor- ough illustration from the study of rhizopods which Ernst Haeckel published in 1862 in his MonograpMe der Radiolarien, and its complete application in the Generelle Morphologic der Organismen by the same naturalist. Haeckel distinguishes in these works, for the first time, between gormless protoplasm, consisting only of plastids called cytods by him, and the germ-containing real cells, the elementary or- ganism of which consists already of two differ- ent essential parts, germ and protoplasm. He conceived the cytods and cells as two differ- ent gradations of plastids, of organic elemen- tary individuals, or as " individuals of the first order," and adopted entirely, in regard to the individual independence of the plastids, the ideas which had been set forth by Eudolf Vir- chow and Ernst Brucke. Virchow, whose Cel- lular- Pathologic contains the most complete application of the cell theory to pathology, called the cells and the " cell territories " be- longing to them the individual hearth or source of life; Briicke designated them as "elemen- tary organisms." The plastids or individuals of the first order, identical with them, were determined by Haeckel phylogenetically, to the effect that eytods and cells must be dis- tinguished as two essentially different orders of formation; i. e., that cells were phylogenet- ically produced in a secondary manner from homogeneous cytods by means of the secretion of a germ by the protoplasm. This distinction is important for the reason that many of the lowest orders of organisms have no germ in the protoplasm; such is the case especially with the moners. These simplest of organ- isms were first discovered by Haeckel in 1864, and described by him in 1868 in his Monogra- phic der Moneren. Cienkowski and Huxley also made valuable investigations of various moners. The latter discovered in 1868 the fa- mous bachybius, a very remarkable kind of moner, which at immense depths covers the bottom of the sea in immeasurable numbers, and which consists of formless and variable protoplasm tissues of different sizes. Among the moners investigated by Cienkowski, the most interesting are the vampire cells, which are formless little bodies of protoplasm that bore into vegetable cells by means of their pointed pseudopodia, kill them, and absorb the protoplasm they find in them. On the basis of these discoveries Haeckel elaborated hia plastid theory and carbon theory, which give the extremest philosophical consequences of the protoplasm theory. In England the mo- nistic philosophy of protoplasm has received the most weighty support from Huxley, whose " Protoplasm, or the Physical Basis of Life " (1868), put it in its true light, and called forth numerous writings for and against it. One of the most recent treatises in favor of it is that of James Ross "On Protoplasm" (1874). Probably the name of plasson will be given to the primordial, perfectly structureless, and ho- mogeneous protoplasm of the moners and other cytods, in contradistinction to the protoplasm of germ-containing cells, which are produced only subsequently, by the differentiation of an
