In this paper its author describes the results of experiments made with two intents—one, to endeavour to ascertain whether there can be a complete arrest of vital action without the death of the egg; the other to ascertain the changes which take place in those instances in which, during incubation, the egg proves unproductive.

The eggs used were chiefly those of the common fowl. The trials to which they were subjected were of three kinds—the airpump, the ice-house, and immersion in lime-water.