From Letter VIII:
 Having in my last been led to say somewhat of the treatment of animals, I cannot be satisfied cursorily to dismiss the subject.
The responsibility that rests on man, for the use of a race of animated and feeling beings, who are in a great degree submitted to his guidance and control, is of more consequences than may be generally supposed. Although they are not to usurp the place of higher intelligences, nor to seduce us from higher duties; yet they have claims on our kindness and attention: and no instances of wanton cruelty, or injurious neglect, ought to be suffered, by those who are entrusted with the use of them. It should ever be remembered, that the same Being formed all ranks of creatures; and He is represented as beholding with complacency all the works of his hands: “And God made all the beast of the earth after his kind, and cattle after their kind, and every thing that creepeth upon the earth after his kind: and God saw that it was good.” The increased  happiness of our present state, derived from the brute creation, it is impossible fully to estimate; and were we deprived of all their aid, we should sink to a condition, in some respects far below that of the brutes themselves. How incalculably more laborious would be our employments, how circumscribed our journeys, how limited our food, and how curtailed our luxuries! Yes; man, with all his arrogance, his pride, and his fancied independance, is indebted to fish and fowl, to beasts, and even to insects, for much that he boasts and hoards. Such considerations, it might be supposed, would be sufficient to lead all ranks to exercise gentleness and kindness towards their helpers and benefactors. But the fallen nature of man shows its depravity, by the licentious abuse of those creatures which cannot move a tongue to plead their own cause, nor lift an arm to defend it.
The noblest animals with which we are acquainted, and those to which we are most indebted, are, there is reason to apprehend, most abused. Had we o horses, the present state of things would be in a great measure changed, and different modes of life must be introduced; and yet, even in this civilized country, numbers of these useful creatures are sacrificed, every year, to cruelty and unreasonable service. We  have high authority for saying, “A merciful man is merciful to his beast:” and perhaps there is scarcely a more decisive proof of a refined and benevolent character, than kind and judicious treatment of animals. One of our best poets deems it so decisive a trait of excellence, as to make the want of it a disqualification for friendship:
I would not enter on my list of friends,
(Though grac’d with polish’d manners and fine sense,
Yet wanting sensibility,) the man
Who needlessly sets foot upon a worm.
This is a department of benevolence which every creature breathing has an opportunity frequently to exercise; and those who have not sufficient influence to prevent oppression and violence, ought, at least, to bear their testimony against it.
Post-horses have, perhaps, a greater share of man’s tyranny and cruelty, than any other of the species. Battered, galled, and strained, often before they are sold for this purpose, we quietly bear to see them yoked to an unmercifully loaded vehicle, and driven with a speed which scarcely youth and vigour would justify, till every limb foams; and they pant and stagger  to the stable, awaiting the next demand, which forces a renewal of their torments. This is such an abuse of borrowed favours, that I shudder while I paint it. If it be forgiven by Him whose “tender mercies are over all his works, and whose are the cattle upon a thousand hills,” it can only be after deep repentance.
We certainly forget our own wants and dependance, when we treat with neglect or unkindness, creatures which so often supply the former, and help to diminish our sense of the latter. Wholly secluded from society, no person present whom we can benefit, not one with whom we might taste enjoyment; animals, and even reptiles become interesting companions. In such cases, tenderness and kindness are advantages to ourselves, as well as to them. The anecdote of the prisoner in the Bastile is an instance of this.” One miserable captive found a spider; he nourished it for two or three years. It grew tame, and partook of his lonely meal. The keeper observed it, and mentioned the circumstance to a superior, who ordered him to crush it! In vain did the man beg to have his spider spared. The keeper obeyed the cruel command; and the unhappy wretch felt more pain when he heard the crush, than he had ever experienced during his long confinement. He  looked round a dreary apartment, and the small portion of light which the grated bars admitted, only served to show him that he breathed where nothing else drew breath.” This was a refinement in punishing which needs no comment; but it might surely teach us to moderate our insolence and soften our asperities towards our fellow-creatures, to find that man, with all his attainments and powers, is so dependant, that even reptiles may become comforters. This thought has just checked me from destroying a large spider which was crawling over my papers. I will give you the spontaneous effusion of the moment, and with it conclude this letter.
Should I kill thee, crawling spider?
By what right, or to what end?
I who crawl but little wider,
I who need the sparing friend.
Go, enjoy thy humble being;
Busy, active, happy be:
See what’s worth a spider’s seeing;
This short life is all to thee.
Though thy mystic, dark vocation,
Proud man eyes with idle sneer;
Yet, throughout the spider nation,
All thy labours may be dear.
Might not beings, higher ranging,
Look on man with like disdain?
Still, without a purpose, changing,
Weaving whimsies of the brain.
Though we boast, and boast with gladness,
A sublimer rank and end;
Yet, in solitary sadness,
Man may hail, e’en thee, this friend.
Go, enjoy thy life’s full treasure
Safe, and uncontroll’d by me;
Power, all power, is only treasure
As it deals felicity.*
* It surely cannot be supposed that these sentiments are intended to operate wherever health, cleanliness, or comfort, are concerned; but the wanton exercise of power, however insignificant its object, is always attended with unhappy effects to the being who inflicts, as well as to that which endures suffering. Whatever renders us inattentive to the claims and feelings of others, has a degrading influence on the mind; and the habits which children acquire, of indiscriminately destroying reptiles and insects, has an inevitable tendency to produce harshness of manners, and despotism of character.
 hudder] 1811