ask, — can Mr. Turner ? If he can, he has done what everybody else has failed in doing, and ought to have immediate credit for the disco- very. I am quite sure he would not wish the facts he has adduced to be considered sufficient proof that "feeling and neurine are sepa- rable," inasmuch as we know that the insects he experimented on possessed neurine, and, by his own confession, he does not deny them feeling. Hence, if he has made the discovery, I presume he has a host of facts, as yet unmentioned and of an entirely novel description, in order to prove his point. If he has not made the discovery, i.e. to say, if he has failed in proving that feeling and neurine are separable, why does he attack me if I have failed in proving that they are insepa- rable ? It is very certain (and his own confessions show it) that he has not proved them to be separable ; and if (as he asserts) I have not proved them to be inseparable, we have both failed in our endeavours, and he has attacked me unjustly. For, after having failed on his part, Mr. Turner, as though he had demonstrated his own point satisfac- tory, coolly requires me to bring forward proofs of mine (viz. that feeling and neurine are inseparable), otherwise, he says, 1 shall be liable to the charge of "building on probabilities and theories." Now, I would ask Mr. Turner, how is this to be proved ? There are evidently two ways. The first is, by observing that the insects in question possess neurine, and then proving from experiment that they have feeling. The second is from analogy.
Regarding the first of these methods, we know that all insects "possess neurine"; — it has been my object in the present paper to prove (as far as possible, independently of analogy) that they " have feeling."
Regarding the second of the above-mentioned proofs, let us say one word, ere we conclude, upon analogy. It was my intention in the ar- ticle Mr. Turner has attacked, to endeavour to demonstrate my point simply and purely from analogy ; the fact of the contrary proposition not being proved by such observations as those we have examined, forming in truth but a subsidiary part of my argument. Now, it is evident from Mr. Turner's attack on my former paper that he rejects analogy altogether, otherwise he could not have possibly considered me " building on theories and probabilities" in arguing from the anal- ogy of the nervous system of insects to our own, that they must possess feeling; i.e., that "neurine and feeling in insects are insepa- rable." But let me warn Mr. Turner of the fearful effects of once de- nying the existence of analogy. So far from being " theoretical," it is the very basis of all inductive reasoning, — the cement which holds
