"Moreover, these 'atoms with souls' do not float in empty space, but in the continuous, extremely attenuated, intermediate substance, which represents the uncondensed portion of the primitive matter" (p. 77). "'Attraction' and 'repulsion' seem to be the sources of _will_—that momentous element of the soul which determines the character of the individual" (p. 45). "The positive ponderable matter, the element with the feeling of like or desire, is continually striving to complete the process of condensation, and thus collecting an enormous amount of _potential_ energy; the negative imponderable matter, on the other hand, offers a perpetual and equal resistance to the further increase of its strain and of the feeling of dislike connected therewith, and thus gathers the utmost amount of _actual_ energy. "I think that this pyknotic theory of substance will prove more acceptable to every biologist who is convinced of the unity of nature than the kinetic theory which prevails in physics to-day" (p. 78). In other words, he appeals to a presumed sentiment of biologists against the knowledge of the physicist in his own sphere—a strange attitude for a man of science. After this it is less surprising to find him ignoring the elementary axiom that "action and reaction are equal and opposite," _i.e._ that internal forces can have no motive power on a body as a whole, and making the grotesque assertion that matter is moved, not by external forces, but by internal likes and desires:— "I must lay down the following theses, which are involved in Vogt's pyknotic theory, as indispensable for a truly monistic view of substance, and one that covers the whole field of organic and inorganic nature:— "1. The two fundamental forms of substance, ponderable matter and ether, are not dead and only moved by extrinsic force, but they are endowed with sensation and will (though, naturally, of the lowest grade); they experience an inclination for condensation, a dislike of strain; they strive after the one and struggle against the other" (p. 78). My desire is to criticise politely, and hence I refrain from characterising this sentence as a physicist should. "Every shade of inclination, from complete indifference to the fiercest passion, is exemplified in the chemical relation of the various elements towards each other" (p. 79). "On those phenomena we base our conviction that even the _atom_ is not without a rudimentary form of sensation and will, or, as it is better expressed, of feeling (_æsthesis_) and inclination (_tropesis_)—that is, a universal 'soul' of the simplest character" (p. 80). "I gave the outlines of _cellular_ psychology in 1866 in my paper on 'Cell-souls and Soul-cells'" (p. 63).