All organic bodies, except the very lowest, consist of cells, small granules of albumen which are only visible when considerably magnified, with a nucleus inside. As a rule the cells also develop an outer membrane and the contents are then more or less fluid. The lowest cellular bodies consist of a single cell; the immense majority of organic beings are multi-cellular, congruous complexes of many cells which in lower organisms remain of a homogeneous type, but in higher organisms develop more and more varied forms, groupings and functions. In the human body, for example, bones, muscles, nerves, tendons, ligaments, cartilages, skin, in a word, all tissues are either composed of cells or originated from them. But in all organic cellular structure, from the amoeba, which is a simple and most of the time skinless albuminous particle with a nucleus inside, up to man, and from the tiniest unicellular desmids up to the most highly developed plant, the manner in which the cells multiply is the same: by fission. The cell nucleus first becomes constricted in the middle, the constriction separating the two halves of the nucleus gets more and more pronounced, and at last they separate from each other and form two cell nuclei. The same process takes place in the cell itself; each of the two nuclei becomes the centre of an accumulation of cellular substance, linked to the other by a strip which is steadily growing narrower, until at last the two separate from each other and continue to exist as independent cells. Through such repeated cell fission the whole animal is gradually developed in full out of the embryonal vesicle of the animal egg, after it has been fertilised, and the replacement of used-up tissues is effected in the same way in the adult animal. To call such a process composition, and to say that to describe it as development is "pure imagination" {D. Ph. 126}, certainly indicates a person who -- however difficult this may be to believe at the present day -- knows absolutely nothing of this process; here it is precisely and exclusively development that is going on, and indeed development in the most literal sense, and composition has absolutely nothing to do with it!
Later on we shall have something more to say about what Herr Dühring understands in general by life. In particular his conception of life is as follows:
"The inorganic world too is a system of self-executing impulses; but it is only at the point where there begins real differentiation, with the circulation of substances through special channels from one internal point and according to a germ-scheme transmissible to a smaller structure, that we may venture to speak of real life in the narrower and stricter sense"{141}.
This sentence is, in the narrower and stricter sense, a system of self-executing impulses (whatever they may be) of nonsense, even apart from its hopelessly confused grammar. If life first begins where real differentiation commences, we must declare that the whole Haeckelian kingdom of Protista and perhaps much else are dead, depending on the meaning we attach to the idea of differentiation.
If life first begins when this differentiation can be transmitted through a smaller germ-scheme, then at least all organisms up to and including unicellular ones cannot be regarded as living. If the circulation of substances through special channels is the hallmark of life, then, in addition to the foregoing, we must also strike from the ranks of the living the whole of the higher class of the Coelenterata (excepting however the Medusae), that is, all polyps and other zoophytes. [43] If the circulation of substances through special channels from one internal point is the essential hallmark of life, then we must declare that all those animals which have no heart and those which have more than one heart are dead. Under this heading would fall, in addition to those already enumerated, all worms, starfish and rotifers (Annuloida and Annulosa, Huxley's classification [44] ), a section of the Crustacea (lobsters), and finally even a vertebrate animal, the lancelet (the Amphioxus). And moreover all plants.
In undertaking, therefore, to define real life in the narrower and stricter sense, Herr Dühring gives us four characteristics of life which totally contradict one another, one of which condemns to eternal death not only the whole vegetable kingdom but also about half the animal kingdom. Really no one can say that he misled us when he promised us "from the ground up original conclusions and views" {525}!
Another passage runs:
"In nature, too, one simple type is the basis of all organisms, from the lowest to the highest", and this type is "fully and completely present in its general essence even in the most subordinate impulse of the most undeveloped plant" {305}.
This statement is again "full and complete" nonsense. The most simple type found in the whole of organic nature is the cell, and it certainly is the basis of the higher organisms. On the other hand, among the lowest organisms there are many which are far below the cell -- the protamoeba, a simple albuminous particle without any differentiation whatever, and a whole series of other monera and all bladder seaweeds (Siphoneae). All of these are linked with the higher organisms only by the fact that their essential component is albumen and that they consequently perform functions of albumen, i.e., live and die.
Herr Dühring further tells us:
