How we cite our quotes: Citations follow this format: (Canto.Line). We used Allen Mandelbaum's translation.
Quote #4
[Virgil to Dante]: "But fix your eyes below, upon the valley,
for now we near the stream of blood, where those
who injure others violently, boil." (Inf. XII, 46-48)
Because Dante ultimately sees violence as a distortion of nature, the landscapes of the Seventh Circle feature some twisted aspects of nature. Here, the boiling river that tortures the tyrants does not flow with water, but with blood. Thus, the violent are punished by natural forces which have been fundamentally perverted.
Quote #5
No green leaves in that forest, only black;
no branches straight and smooth, but knotted, gnarled;
no fruits were there, but briers bearing poison.
Even those savage beasts that roam between
Cecina and Corneto, beasts that hate
tilled lands, do not have holts so harsh and dense. (Inf. XIII, 4-9)
In the ring where the suicides reside, not even nature’s growing flora can flourish. Here, trees and plants that normally sprout in healthy shades of green rot to black and do not sprout nourishing fruits, but poisoned thorns. The reference to the living "beasts" between "Cecina and Corneto" implies that even these savage creatures could not survive in such a place. Nature decrees that nothing can live and grow in a place where men have taken their own lives.
Quote #6
Above that plain of sand, distended flakes
of fire showered down; their fall was slow –
as snow descends on alps when no wind blows.
Just like the flames that Alexander saw
in India’s hot zones, when fires fell,
intact and to the ground, on his battalions,
for which – wisely – he had his soldiers tramp
the soil to see that every fire was spent
before new flames were added to the old;
so did the never-ending heat descend;
with this, the sand was kindled just as tinder
on meeting flint will flame – doubling the pain. (Inf. XIV, 28-39)
The environment designed for punishing blasphemers perverts nature by raining fire, instead of snowflakes, to the ground. So instead of bringing relief to the sandy desert and allowing things to grow, the fiery rain increases the heat, making it eternally uncomfortable for the sinners trapped there.