546 NOVUM ORGANUM. [bOOK tt 



parts with those substances, so that when surrounded by them 

 it draws itself back, and its avoidance of these intervening ob- 

 stacles is greater than its desire of reuniting itself to its homo- 

 geneous parts; which is what they term the mortification of 

 quicksilver. Again, the difference in weight of oil and water is 

 not the only reason for their refusing to mix, but it is also owing 

 to the little affinity of the two ; for spirits of wine, which are 

 lighter than oil, mix very well with water. A very remarkable 

 >nstance of the motion in question is seen in nitre, and crude 

 /lodies of a like nature, Avhich abhor flame, as may be observed 

 )(! gunpowder, quicksilver, and gold. The avoidance of one pole 

 if the magnet by iron is not (as Gilbert has well observed), 

 strictly speaking, an avoidance, but a conformity, or attraction 

 to a more convenient situation. 



Let the eleventh motion be that of assimilation, or self- 

 multiplication, or simple generation, by which latter term we 

 do not mean the simple generation of integral bodies, such 

 as plants or animals, but of homogeneous bodies. By this 

 motion homogeneous bodies convert tliose which are allied 

 to them, or at least well disposed and prepared, into their 

 own substance and nature. Thus flame multiplies itself over 

 vapours and oily substances, and generates fresh flame ; the air 

 over water and watery substances multiplies itself and generates 

 fresh air ; the vegetable and animal spirit, over the thin particles 

 of a watery or oleaginous spirit contained in its food, multiplies 

 itself and generates fresh spirit ; the solid parts of plants and 

 animals, as the leaf, flower, the flesh, bone, and the like, each of 

 them assimilate some part of the juices contained in their food, 

 and generate a successive and daily substance. For let none 

 rave with Paracelsus, who (blinded by his distillations) would 

 have it, that nutrition takes place by mere separation, and that 

 the eye, nose, brain, and liver, lie concealed in bread and meat, 

 the root, leaf, and flower, in the juice of the earth ; asserting 

 that just as the artist brings out a leaf, flower, eye, nose, hand, 

 foot, and the like, from a rude mass of stone or wood by the 

 separation and rejection of what is superfluous ; so the great 

 artist within us brings out our several limbs and parts by sepa- 

 ration and rejection. But to leave such trifling, it is most cer- 

 tain that all the parts of vegetables and animals, as well the 

 homogeneous as organic, first of all attract those juices contained 

 in their food, which are nearly common, or at least not very 

 different, and then assimilate and convert them into their own 

 nature. Nor does this assimilation, or simple generation, take 

 place in animated bodies only, but the inanimate also participate 

 in the same property (as we have observed of flame and air), and 

 that languid spirit, which is contained in every tangible animated 

 substance, is perpetually working upon the coarser parts, and 



