Another topic from the same quarter is, that Professor Erni of Yale College has been making an interesting series of experiments on fermentation--a process of which the original cause has never yet been satisfactorily explained, and is still a moot-point with chemists. They tell us it is one by which complex substances are decomposed into simpler forms, as some suppose, by chemical action; others, by development of fungi, different in different substances. Among the experiments, it was observed that the yeast of cane-sugar solution produced no fermentation whatever when poisoned with a small quantity of arsenious acid; with oil of turpentine, and creasote, similar negative results were obtained. The introduction of cream-of-tartar along with the arsenic neutralised its effect, but not so with the other two; and, singularly enough, the appearance of the liquor always shewed when the poisoning was complete; 'the nitrogenous layer on the cell-membrane seeming to have undergone a change similar to that produced by boiling.' Judging from the results, Professor Erni believes 'that alcoholic fermentation is caused by the development of fungi. He could never trace the process without observing at the very first evolution of carbonic acid, the formation of yeast-cells, although it is very difficult to decide certainly which precedes the other.' His own opinion is in favour of the commencement by the yeast-cells. Another noteworthy subject, is Dr W.J. Burnett's paper to the American Association, 'On the Relation of the Distribution of Lice to the Different Faunas,' in which he endeavours to demonstrate, that the creation of animals was a multiplied operation, carried on in several localities, and that they do not derive from one original parent stock. Different animals have different parasites; but, as he shews, the same species of animal has the same parasite, wherever it may be found. According to Latreille, the _pediculus_ found in the woolly heads of African negroes 'is sufficiently distinct from that of the Circassian to entitle it to the rank of a distinct species;' from which, and similar instances, the doctor concludes: 'Whatever may be urged in behalf of the hypothesis of the unity of the animal creation, based upon the alleged metamorphosic changes of types, it is my opinion that the relations of their parasites, and especially the lice which are distributed over nearly all of them, must be considered as fair and full an argument as can be advanced against such hypothesis, for it is taking up the very premises of the hypothesis in opposition.' Dr Burnett will perhaps find Sir Charles Lyell ready to break a lance with him on the point at issue. Something interesting to workers in metal has been brought before the Franklin Institute at Philadelphia--it is a method of giving to iron the appearance of copper, contrived by Mr Pomeroy of Cincinnati, who thus describes it--rather laboriously, by the way:--