He refutes the great principle of Leibnitz, which was so brilliantly adopted by Darwin, that changes occur by degrees, by "fine shades," by slow variations, as the result of successive adaptations, and that there is no jumping-off place in nature. On the contrary, life often passes suddenly from one form to another, by abrupt and capricious leaps, by irregular and disorderly steps, and it is in the egg that Fabre sees the first lineaments of these mysterious and spontaneous variations. Species are therefore born as a whole, each at the same time, AT THE SAME MOMENT, "bringing into being its new organism, with its individual properties and peculiarities, its indelible and innate faculties and tendencies, like "so many medals, each struck with a different die, which the gnawing tooth of time attacks only sooner or later to annihilate it." However, Fabre affirms the continuity of progress; he believes in a better and more merciful future, a more complete humanity, ruled by more harmonious or less brutal laws. With what profound intelligence and what generous enthusiasm he seeks to conjecture what this future might be, in his beautiful observations on the young of the Lycosa (9/17.), which can live for weeks and months in absolute abstinence, although we can perceive no reserve of nutriment! We know no other sources of animal activity save the energy derived from food. Vegetables draw the materials of their nourishment from the soil and the air, and the sunlight is only an intermediary which enables the plant to fix its carbon. The animal species in turn borrow the elements indispensable to their existence from the vegetable world, or restore their flesh and blood with the flesh and blood of other animals. Now the young Lycosae "are not inert on their mother's back; if they fall from the maternal chine they quickly pick themselves up and climb up one of her legs, and once back in place they have to preserve the equilibrium of the mass. In reality they know no such thing as complete repose. What then is the energetic aliment which enables the little Lycosae to struggle? Whence is the heat expended in action derived?" Fabre sees no other source than "the sun." "Every day, if the sky is clear, the Lycosa, loaded with her little ones, crawls to the edge of her well, and for long hours lies in the sun. There, on the maternal back, the young ones stretch themselves out, saturate themselves in the sunshine, charging themselves with motor reserves, steeping themselves in energy, directly converting into movement the calorific radiations coming from the sun, the centre of all life." The Scorpion also is able to live for months without nourishment, restoring directly, in the form of movement, "the effluvia emanating from the sun or from other ambient energies--heat, electricity, light--which are the soul of the world."