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Rh The vital resistance of certain germs to heat is strikingly illustrated in the third essay, one infusion being there proved to maintain its potentiality of life intact after eight hours' continuous exposure to the temperature of boiling water. Under the plain guidance of the germ theory, it is, however, shown that an infusion of this stubborn character may be infallibly sterilized by discontinuous heating, in one hundredth part of the time requisite when the boiling is continuous. Another question, to my mind of fundamental importance, is also disposed of in Essay III, where it is shown that the germs which exhibited the fore-going resistance are neither contained in the air, nor attached to the surface of the vessel, above the liquid, but that they manifest their extraordinary vitality in the body of the liquid itself.

On public sympathy the sanitary physician has mainly to rely for support, in a country where sanitary matters are left so much in the hands of the public itself as they are in England. But sympathy without cause—that is to say, without some basis of knowledge—is hardly to be expected. It is as a contribution to such knowledge that these essays have been collected, and thrown into their present handy form.

August, 1881.



HERE are really privileged persons within the scientific domain. M. Gaston Planté, whose name is associated with a most important advance in electrical knowledge, enjoyed the opportunity, in 1855, of making, in a wholly different direction, a discovery in paleontology that was of great interest. In a very curious bed of loam of the Eocene tertiary formation, called the ossiferous conglomerate of Men don, and which has now nearly disappeared, he found a bird's tibia, which measured, though it was not whole, forty-five centimetres in length. At first sight this great bone appeared to exhibit considerable analogies with the corresponding part of the swan, and differed from it only by the presence of the subtrochlean groove, and by the relatively high situation of the osseous arch, and the outer muscular attachment. But what a contrast in the size! An idea of it may be gained from Fig. 2, A and B, which represent the tibia of the Meudon bird to which Constant Prevost fittingly gave the name of Gastornis (Gaston's bird)—and the tibia of the common swan, on the same scale. After M. Plante's discovery, a geological formation corresponding exactly with the conglomerate of Meudon was found at Reims. Quite recently, Dr. Lemoine has established the connection between the beds 