[Reports the results of experiments on the vitality of impregnated fish ova carried out in November and December 1855. The ova of Charr were exposed to temperatures ranging from 70^o F to 84^o F for various periods of time. Ten experiments to ascertain the maximum temperature at which the ova will stay alive were carried out. A second series of experiments was also performed in which a trial of the vitality of the ova was made by packing them in wet wool and sending them a distance by post. Considers it as proved that the power of resisting an undue temperature is possessed in a higher degree by the ova in an advanced, than in an early stage of development; and that the power of retaining life in moist air in like degree increases with age. It may further be inferred that the ova of other species of the Salmonidæ, were they similarly exposed, would afford similar results.]¹