Dear Sir

On reading a short review of your new work on Expression in Man & Animals last night, I was struck by your remarks on Antithesis.

At one place,—after describing the energy of the dog in a hostile mood, & the reverse movements when the dog discovers the supposed enemy to be his own master,—you remark “not one of the above mentioned movements, so clearly expressive of affection, are of the least direct service to the animal &^c. and are only explicable on the ground of antithesis &^c.”¹ Now Sir, it may appear presumption in me attempting to correct so distinguished an observer as yourself, but I cannot help thinking that a much more satisfactory explanation can be given for the change in the dogs movements.

You are doubtless aware of the fact, well known in Art, that Lines tending upwards indicate energy, power, joy &^c. while Lines tending downwards indicate the reverse or weakness, sadness, horror &^c. Horizontal Lines again showing repose. Here lies, I suspect, the true explanation. The Lines in the case of the dog about to fight, so well described by you, clearly point to the truth of the first statement; while the second law is as clearly pointed out by your description of the dog when he finds out his mistake.

The explanation, to my mind, is that the dog is ashamed of his mistake. He therefore first expresses his sorrow by changing his Lines & giving them all a downward direction— When the Master is reconciled, as discovered by his face or voice, then the dog expresses his affection by leaping up &^c.

In the case of the angry Cat,² also mentioned by the Reviewer, the only down tending lines are the ears— All the others are uptending, such as the arched back, erect tail, hair both on back & tail all bristling— In this case I read that the up lines give energy to the hate expressed by the ears forced back; for the ear muscles are not at rest, on the contrary they are active for the superior edge of the ear is actually flattened.

These considerations regarding Lines appear to afford a more rational explanation than the ground of Antithesis.

Allow me to mention a curious case of incongruity of lines, which always looks absurd even to a child—unless indeed there be enough of energy to cause fear. When a dog is let off the chain for a run, we not unfrequently see him dart off with his tail down, & his hind quarters crouching; while his head & ears are in the attitude of repose! In this curious fashion he describes a few curves with great energy & then becomes himself again. Is this same incongruity of lines not the true meaning of the shrugging of the shoulders observed by you as so general in Man?³

It is however in the human face & in Ladies’ dress where the effect of Lines can be best observed— For instance—depress the outer angles of the eyes & mouth; then elevate these; then turn the one up & the other down & mark the difference in expression— Again take a Widow with her peculiar cap & let her hair be curled—how unpleasant the effect? Now let her hair be braided & how harmonious is the result?⁴ &^c. &^c.

Observing the effects of the direction of lines has been a favourite amusement of mine for years & I am forced to the conclusion that the expression in the direction of Lines is the only universal language of Man & the higher Animals, & I do not doubt but you will come to the same conclusion if you can spare time to attend to the subject—

My time for reading is very limited and I am only now engaged with your work on the Origin of Species— Allow me to thank you sincerely for the instruction & pleasure which that book is giving me, & for the glorious glimpses it gives us of the vast scheme of creation. The “several creations” theory is perhaps as far as man could grasp in earlier times, & still is enough for many—⁵ But how vastly greater must we conceive the Power to be, who calls forth organic life & gives it laws to adapt itself to all time & all circumstances! You Sir have opened out a new & wonderful truth which will ere long, in my humble opinion, do more to exalt our thoughts of the Almighty than any ideas started since the time of Newton.⁶

I beg you to excuse me troubling you, but to one who is so humble & earnest a student after truth as you evidently are, I thought that my theory of Lines would probably be neither insignificant nor uninteresting—

I am | Yours very respectfully | W^m. Main

To | Charles Darwin Esq^r. | Down | Bromley— Kent