Had we our senses — Shrewmouse

Had we our senses 1
But perhaps 'tis well they're not at Home
So intimate with Madness
He's liable with them

Had we the eyes without our Head- 5
How well that we are Blind-
We could not look upon the Earth-
So utterly unmoved-
(F.1310/J.1284)
[1] we:: earth-shrews, or shrew-mice, hinted in line 7.
[3] Madness:: mania, rabies; rumored that shrew bites are venomous.
[4] liable:: the malignant influence of the shrew-mouse.
[5, 6] eyes, Blind:: shrew-mouse can hardly see.
[7] Earth:: a hint on earth-shrew, also called shrew-mouse or just shrew.
[8] unmoved:: still; passionless, frigid.

The shrew-mouse seems to form a shade in the order of diminutive animals, and to fill up the interval between the mole and the rat; . . . From this noisome odour a notion has been imbibed by ignorant people, that it is possessed of a considerable degree of venom; to which they attribute some diseases of horses and other cattle; ─ The Naturalist's Cabinet (1806)