Decembee 27, 1901.] 



SCIENCE. 



1001 



?<- 



resentation (Spiegelbild) of that of the upper 

 waters. 



The last sentence in the body of the work is 

 well worth quoting for the beauty and grandeur 

 of the conception involved : 



' ' Denn alles, was oben im Spiel der Wellen 

 und im Sonnenlicht lebt und vegetiert, muss end- 

 lich doch noch in irgend einer Form zur Tiefe 

 gelangen, um in der dunklen, von keiner Welle 

 erregten Riesengrabstatte des Meeresgrundes 

 den Kreislauf des StofFes zu vollenden." 



Following the body of the work are twenty 

 closely printed pages of notes of a more tech- 

 nical character, embodying the actual facts 

 which form the basis for the statements and 

 conclusions of the author. These are of real 

 value to those who study more carefully the 

 fascinating problems of the deep. 



The work as a whole will form a welcome 

 addition to the library of the general student, 

 and the specialist will find it well worthy his 

 careful perusal and frequent consultation. 



C. C. Nutting. 



%^ 



Agricultural Bacteriology : A Study of the Eela- 

 tion of Bacteria to Agriculture with special 

 Reference to the Bacteria in the Soil, in 

 Water, in the Dairy, in Miscellaneous Farm 

 Products, and in Plants and Domestic Animals. 

 By H. W. Conn, Ph.D. Philadelphia, P. 

 Blakiston'sSon&Co. 1901. Pp.412. Figs. 

 40. 



This is a new book on a new subject. There 

 have been books treating of separate phases of 

 the subject, as dairy bacteriology, but heretofore 

 no book has been issued in English which has 

 attempted to cover the whole range of bacteri- 

 ology in its relations and applications to agri- 

 culture. As the sub-title explains, it has 

 special reference to the bacteria in the soil, in 

 water, in the dairy, in miscellaneous farm 

 products and in plants and domestic animals. 

 Professor Conn shows that while in the popu- 

 lar mind bacteria have come to be almost 

 synonymous with disease, they are intimately 

 associated with many normal processes which 

 are going on in the soil, water and elsewhere, 

 and are important and very often essential fac- 

 tors in the operations of farming as well as in 

 every-day life : ' ' From beginning to end the 



occupations of the agriculturist are concerned 

 in the attempt to obtain the aid of these micro- 

 organisms when they may be of advantage, 

 and in preventing their action in places where 

 they would be a detriment"; and he adds 

 that " farming without the aid of bacteria is an 

 impossibility." As yet only a beginning has 

 been made in studying their application. la 

 the section on bacteria in the soil, the author 

 shows that they have important relations to 

 agricultural processes in at least five different 

 directions, namely, in the decomposition of 

 rocks, the fixation of free atmospheric nitro- 

 gen in the soil, the decomposition of all com- 

 plex organic bodies and compounds in the soil, 

 the formation of nitrates, and, in connection 

 with the legumes, in reclaiming nitrogen from 

 the air. He prophesies that " in the future the 

 problem of the proper treatment of soil for the 

 use of agriculture will be, in a very large de- 

 gree, a problem of the proper control of bac- 

 teria. Agriculturists must learn to stimulate 

 the bacterial actions which are advantageous, 

 and check those which are disadvantageous, 

 if they would insure the continuance of soil 

 fertility." There is perhaps no phase of agri- 

 culture where bacteria play such an important 

 part as in the dairy. It is appropriate, there- 

 fore, that this subject, to which Professor Conn 

 has himself been an important contributor, 

 should receive quite extended treatment. The 

 advances made in the control of bacteria in 

 milk, as a result of better understanding of 

 their sources and of pasteurization, have con- 

 tributed to a better milk supply of cities, as well 

 as to superior quality of the butter produced. 

 The author contends that the introduction of 

 pure cultures for ripening the cream in butter- 

 making has resulted in improving the general 

 quality of butter and has led to greater care in 

 the preparation of the 'starter' where pure 

 cultures are not employed. The part played 

 by enzymes, especially galactase and rennet, in 

 the ripening of cheese is pointed out, but the 

 author is inclined to ascribe considerable im- 

 portance to lactic bacteria in this connection. 

 Elsewhere the importance of enzymes in ex- 

 plaining various phenomena formerly ascribed 

 to the direct action of bacteria is discussed at 

 some length. This opens up an interesting 



