external variation—but surely it would be a matter of surprise if it did not exist, considering the variation of external circumstances—artic cold and tropical heat—flowery savannas and arid deserts—civilization and barbarism—liberty and oppression—scantiness of food and an abundant supply—nutritious food and a feebly supporting fare—the feeling of security and the sense of danger. [Illustration] If the existence of varieties of structure and complexion offers no argument against the common nature and origin of the millions of mankind in the slightest degree valid, their identity as a species is strongly supported by adverting to the general laws of their animal economy. These have reference to the manner of their birth, the period of gestation, the duration of life, and the casualties in the form of diseases to which they are subject; and, in all these respects, a general coincidence proclaims the unity of the human population of the globe. As to longevity, it is the case indeed that the barbarian tribes are shorter-lived than the cultivated races; but this is owing to the physical hardships under which they suffer, and to ignorance of the appropriate remedies to use under the assailments of sickness, freedom from the former and a knowledge of the latter being possessed by all civilized nations. Facts prove that, in circumstances favorable to extreme longevity, the Europeans, the most polished communities, have no preëminence over the tribes of Africa, among the least advanced in the social scale. Mr. Easton, of Salisbury, gives the following instances of advanced age from the Europeans and Asiatics— In A. D. Aged. Appollonius at Tyana 99 130 St. Patrick 491 122 Attila 500 124 Leywarch Hêw 500 150 St. Coemgene 618 120 Piastus, King of Poland 861 120 Thomas Parr 1635 152 Henry Jenkins 1670 169 Countess of Desmond 1612 145 Thomas Damme 1648 154 Peter Torton 1724 185 Margaret Patters 1739 137 John Rovin and Wife 1741 172 & 164 St. Mougah or Kentigern 1781 185