5 Clifford St
Aug. 5 1867
Dear D⟨arwin⟩
I have ⟨referred to⟩ Sir C Bells ⟨wo⟩rk ⟨in⟩ regard to the subject of your query.1 I suppose there is no doubt that in violent sneezing &c the eyes are protected by the distinctive closing of the lids— and that when the closure is Spasmodic & strong, the vessels of the eyeballs, tending to be engorged under the strain put upon them are mechanically supported by the External Compression and all the more if the organ by a certain degree of engorgement of its ⟨own⟩ ⟨& the⟩ neighbouring vessels begins ⟨to be made more⟩ pro⟨minent for then⟩ it wou⟨ld⟩ be more ⟨exposed to th⟩e pressure of the ⟨of the orbicularis⟩ muscle. I should ⟨be in⟩cline⟨d⟩ to place little reliance on the experiment related by Sir Charles, as to opening the lids of a screaming infant & finding the eyes at first pale becoming red (if that be his meaning)—because the mechanical restraint & pressure of the fingers at the moment of inspection would be likely to modify the condition—2 Sir C. Bells remarks are always ingenious & often full of meaning, but he was ⟨perhaps not always a rigidly⟩ exact experimenter.
As ⟨to your other question,⟩ I should ⟨say⟩ that ⟨in intent looking whether at near⟩ or distant ⟨objects the contraction⟩ of the brows & of some other parts near the eye under the influence of intense, attention given to the perceptions of the sense—is attended with (often) some aid to acuteness of sight by partial occlusion of the pupil—& may partly sustain the consensual movements of the two eyes—by giving a firmer external support while the globes are brought to binocular vision by their ⟨own pr⟩oper muscles—3
⟨I am⟩ delighted to hear you ⟨are⟩ likely soon to give us som⟨e more of⟩ your deep thoughts ⟨and wide gen⟩eralizations.4 Be sure no one more appreciates your labours than myself.— I think your views the only rational ones on the grand subject of the course of life upon our planet. You seem to be on the high road to a future which yet I suppose will be ever distant from the most advanced philosophers of human mould. But with long looking towards things unseen as yet our power of sight may improve with improvement of the material organs of mental & physical sight & our race may know when it is come to somewhat higher than its at present.
Yrs ever most sincerely | W. Bowman
Please cite as “DCP-LETT-5596,” in Ɛpsilon: The Charles Darwin Collection accessed on