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192 but manifestations of the same essential process; they are all linked together, and as our knowledge of the nature of the molecular processes connected with life advances, we will be better able to explain and correlate such phenomena as contraction, secretion, and electrical action.

I have now the pleasure of showing you a large live gymnotus which has been kindly lent for demonstration by Mr. P. L. Sclater, the Secretary of the Royal Zoological Society. The fish, in charge of his keeper, is in this large tank. He is about four feet in length, and it is satisfactory to know that he has lived for seven years in the "Zoo," far away from his own Amazon, and that, with good feeding, he has nearly doubled in size. It is quite proper that the fish should first of all give a shock to a physiologist who is endeavouring to demonstrate his properties, so I seize hold of these handles while the keeper touches the fish with the ends of insulated wires. Ah! I have got a pretty smart shock, felt up to the elbow, like the discharge of a Leyden jar. Next we shall lead off a little to the galvanometer, making the instrument as insensitive as