That this mutual exchange and nutrition may take place between the general cells of two bodies is made all the more probable from the experiments already alluded to with regard to chemical fertilization—whereby it has been shown that some ova or egg-cells may be started on a process of subdivision and growth by treatment with certain chemicals, such as weak solutions of strychnine, or common salt, apart from any fertilization by a spermatozoon.[21] Now since—when the body is once fairly formed—its further growth and sustenance is maintained by continued division and subdivision of the body-cells, this stimulus to growth may easily (we may suppose) be supplied by the subtle radiations and reactions from another body within whose sphere of influence it comes—radiations and reactions sufficiently subtle to pass through the tissues to the various cells, and of course sufficiently characteristic and individual to be in some cases, as we have supposed, highly vitalizing and stimulating—though in other cases of course they may be poisonous and harmful. Of course, also, it is only love that supplies and is the vitalizing relation. So intense, at times, is this vitalizing force, and so ardent the need of it, that the whole body leaps and throbs in pain. Plato, in his poetic way, explains the scorching sensation in all the skin and tissues by feigning that it is caused by the wing-feathers of the soul sprouting everywhere (_i.e._ according to our view, in every little cell). Nevertheless, his words on the subject are singularly pregnant with meaning. For he says (in the _Phædrus_): “Whenever indeed by gazing on the beauty of the beloved object, and _receiving from that beauty particles which fall and flow in upon it_ (and which are therefore called ‘desire’), the soul is watered and warmed, it is relieved from its pain, and is glad; but as soon as it is parted from its love, and for lack of that moisture is parched, the mouths of the outlets by which the feathers start become so closed up by drought, that they obstruct the shooting germs; and the germs being thus confined underneath, in company of the desire which has been infused, leap like throbbing arteries, and prick each at the outlet which is closed against it; so that the soul, being stung all over, is frantic with pain.”[22]