The whole theory which must explain and justify the predilection for evil has, besides, been invented as an after-thought. The inclination for what is evil and disgusting existed first, and was not a consequence of philosophical considerations and self-persuasion. We have here merely another case of that method of our consciousness, so often attested in the course of these inquiries, which consists of inventing rational causes for the instincts and acts of the unconscious. In the predilection of the Parnassians for the immoral, criminal and ugly, we have to deal merely with an organic aberration, and with nothing else. To pretend that inclinations of this kind exist in all men, even in the best and sanest, and are merely stifled by him, while the Parnassians give the rein to theirs, is an arbitrary and unproved assertion. Observation and the whole march of the historical development of humanity contradict it. There may be repulsion and attraction in nature--no one denies it. A glance at the magnetic poles, at the positive and negative electrodes, suffices to establish this fact. We find this phenomenon again among the lowest forms of life. Certain materials attract, others repel them. There is no question here of an inclination or an expression of the will. We must rather consider the process as purely mechanical, having its reason probably in molecular relations which are still unknown to us. Microbiology gives to the attitude of micro-organisms towards attractive and repulsive matter the name of ‘chemotaxis’ or chimiotaxia, invented by Pfeffer.[275] In higher organisms the conditions are naturally not so simple. Among them also, it is true, the ultimate cause of inclinations and aversions is certainly chimiotactic, but the effect of chimiotaxia must necessarily manifest itself under another form. A simple cell such as a bacillus, for example, is repelled directly when it penetrates into the radius of a chimic body which repels it. But the cell constituting a portion of a higher organism has not this liberty of movement. It cannot change its place independently. If it is now chimiotactically repelled, it cannot escape from the pernicious action, but must remain exposed to it, and submit to the disturbances in its vital activity. If these are sufficiently serious to injure the functions of the whole organism, the latter obtains knowledge of it, endeavours to perceive their cause, discovers it also, as a general rule, and does for the suffering cell what the latter cannot do alone, namely, shields it from the repelling action. The organism necessarily acquires experience in its defence against pernicious influences. It learns to know the circumstances in which they appear, and no longer permits matters to reach the stage of the really chimiotactic effect, but for the most part evades disturbing matters before they can exert a really direct repulsion. The knowledge acquired by the individual becomes hereditary, transforms