Equally inapplicable is No. 4: and of No. 5 I can only repeat, first, that I do not make Life _like_ magnetism, or _like_ electricity; that the difference between magnetism and electricity, and the powers illustrated by them, is an essential part of my system, but that the animal Life of man is the identity of all three. To whatever other system this objection may apply, it is utterly irrelevant to that which I have here propounded: though from the narrow limits prescribed to me, it has been propounded with an inadequacy painful to my own feelings. The ridicule in No. 6 might be easily retorted; but as it could prove nothing, I will leave it where I found it, in a page where nothing is proved. A similar remark might be sufficient for the bold and blank assertion (No. 7) with which the extract concludes; but that I feel some curiosity to discover what meaning the author attaches to the term analogy. Analogy implies a difference in sort, and not merely in degree; and it is the sameness of the end, with the difference of the means, which constitutes analogy. No one would say the lungs of a man were analogous to the lungs of a monkey, but any one might say that the gills of fish and the spiracula of insects are analogous to lungs. Now if there be any philosophers who have asserted that electricity as electricity is the _same_ as Life, for that reason they cannot be _analogous_ to each other; and as no man in his senses, philosopher or not, is capable of imagining that the lightning which destroys a sheep, was a means to the same end with the principle of its organization; for this reason, too, the two powers cannot be represented as analogous. Indeed I know of no system in which the word, as thus applied, would admit of an endurable meaning, but that which teaches us, that a mass of marrow in the skull is analogous to the rational soul, which Plato and Bacon, equally with the “poor Indian,” believe themselves to have received from the Supreme Reason. It would be blindness not to see, or affectation to pretend not to see, the work at which these sarcasms were levelled. The author of that work is abundantly able to defend his own opinions; yet I should be ambitious to address _him_ at the close of the contest in the lines of the great Roman poet: “Et nos tela, Pater, ferrumque haud debile dextrâ Spargimus, et nostro sequitur, de vulnere sanguis.”