Will you oblige me by looking with a strong lens at the bit of comb, brushing off with a knife the upper thickened edges, and then compare, by eye alone, the thickness of the walls there with the thickness of the basal plates, as seen in any cross section.

I should very much like to hear whether, even in this way, the difference is not perceptible.

It is generally thus perceptible by comparing the thickness of the walls of the hexagon (if not taken very close to the angle) near to the basal plates, where the comparison by eye is of course easier.

Your letter actually turned me sick with panic; from not seeing any great importance [in the] fact, till I looked at my notes, I did not remember that I made several measurements.

I have now repeated the same measurements, roughly with the same general results, but the difference, I think, is hardly double.
I should not have mentioned the thickness of the basal plates at all, had I not thought it would give an unfair notion of the thickness of the walls to state the lesser measurements alone.
LETTER 74.