What does ' as can be remarked in' mean?

Answer 1

Do you mean in a sentence like "The criminal brain is much less developed, as can be remarked in the example in the jar on my desk here"? (People used to think the brain reflected moral states as can be remarked in the scene in the 1931 film Frankenstein which I am referring to here)

To remark upon something is to notice it. So this kind of sentence expresses a general statement, and then asks you to notice the concrete expression of that statement, like the brain on the desk. The phrase "as can be remarked in" connects the general principle to the specific example, as can be remarked in this sentence you are reading now.