Abstract
The whole subject of the nature of life and of the connection between vitality and the matter by which it is manifested, is one of such vastness and complexity that it would be impossible to treat it adequately, save in a special and extended treatise. Upon the present occasion, I need hardly say, I shall attempt nothing further than to give a brief and general sketch of the fundamental phenomena manifested by living beings, and of the more important considerations which, it appears to me, should guide us in arriving at some judgment as to the essential nature of that which we call "life." The mere historical retrospect of the various views which have been at different times entertained and published as to the nature of vitality, however brief and bald, would occupy no inconsiderable time, and I shall content myself here with a short discussion of the latest phases into which this question has entered; while I must entirely omit all considerations relating to the subject, still a contested one, of the origin of living matter.