Juices varied in colours and in powers, to harm or to help, or neither to harm nor to help, varied in amount, excess or defect, in combination of some but not of others. And to the warming of all it harms or helps, to the cooling it harms or helps, to the power it harms or helps. Of power varied natures. Humours corrupting whole, part, from without, from within, spontaneous, not spontaneous; spontaneous for us, not spontaneous for the cause. Of the cause, part is clear, part is obscure, part is within our power and part is not. Nature is sufficient in all for all.