of society to another has been sharp or sudden. "Time has been an essential element in the formation of these strata."
The various lines along which development has taken place are thus summarized: 1. Subsistence; 2. Government; 3. Language; 4. The Family; 5. Religion; 6. Home-Life and Architecture; 7. Property. In the author's plan each of these lines is followed in detail, and the characteristic features of each in the successive stages of culture are presented in their order. Thus subsistence is shown to have been at first upon fruits and roots. Next in order came fish, then farinaceous substances; later, meat and milk; and lastly arose agriculture. It is obvious that food and the methods of procuring and preparing it have direct relation to culture, so that the status of a primitive people may be determined very nearly by that standard.
The author's elaborate discussion of the genesis of the family will be read with close attention, and will doubtless excite criticism. We can only in the briefest manner state without comment some of the aspects and forms of the primitive family as presented in the work. The lowest status of society is characterized by promiscuous intercourse. The next stage was intermarriage of brothers and sisters. Out of this arose the consanguineous family, or family representing consanguinity and affinity, giving rise finally to the organization of the family on the basis of sex. In this a check was given to the intermarriage of brothers and sisters, and following this occurred marriage between single pairs. A higher stage was the patriarchal family arising from pastoral life. Lastly arose the monogamian family, in which paternity of children is assured, with ownership of property, and lineal descent.
Throughout the work it is made apparent that the earliest steps in progress were 'taken with difficulty, and required a long period of time. But changes became more rapid as society advanced. If 100,000 years be assumed as the period of man's existence on earth, 60,000 years, on the theory of progressive development, must be assigned to savagery, 20,000 years to the lower stage of barbarism, 15,000 years to the middle and upper stages of barbarism, leaving but 5,000 years for the period of civilization. It would thus appear that during three-fifths of the whole human period man was scarcely more than a child. Whatever changes of fact or of conclusion future inquiries may render necessary in the present work, it will remain a monument of the painstaking labor of the author.
Principles of Theoretical Chemistry, with Special Reference to the Constitution of Chemical Compounds. By Ira Remsen, M. D., Ph. D., Professor of Chemistry in the Johns Hopkins University. Philadelphia: Henry C. Lea, 1877. Pp. 231. Price, $1.25.
This is a contribution to chemical literature of special fitness and importance at the present time, when the science is passing into a new stage. Prof. Remsen devotes himself to the theoretical aspects of what is called the new chemistry, which he treats with discrimination, presenting its claims with clearness and weighing its defects with fairness. He aims to show exactly upon what basis our present conceptions of chemical constitution rest. The need of a sifting discussion of the subject is assumed to rest upon the fact that the more recent views, be they good or bad, are held by nearly all the working chemists of the day. In regard to the execution and purposes of his book, the author remarks in his preface: "The subject is, of course, not exhausted; many things have purposely been left out, either because they have not yet reached such a stage of development as to entitle them to a place among the fundamental principles, or because it was thought better to emphasize more strongly those principles which are treated. Should the reader miss anything which he expected to find, he will please carefully consider whether the grounds referred to are a sufficient excuse for the omission. The imperfections that will be noticed are, partly at least, due to the imperfection of our knowledge on some of the subjects discussed. For instance, it seems to be impossible for us at present to treat the subject of valence in such a way as to lead to satisfactory results, mainly for the reason that we know so little in regard to it. Whatever view of this property one may take, he will find some difficulties which he cannot surmount."
