IV PREFACE. 



ness of the book by comprehensive, concise contributions on 

 subjects in their particular lines of study : Professors W. 

 H. Caldwell, J. A. Craig, John W. Decker, L. H. Dewey, F. 

 H. Farrington, B. E. Fernow, E. S. Goff, A. W. Richter, 

 H. L. Russell, Thos. Shaw, Wm. P. Wheeler; and Messrs. 

 John Boyd*. W. G. Clark, M.D.C., N. S. Fish, J. D. Fred- 

 criksen, H. B. Gurler, S. Hoxie, J. Noer, M.D., J. H. 

 Pickrell, H. B. Richards, L. P. Sisson, J. McLain Smith, 

 and C. M. Winslow. 



While all possible care in the preparation of the manu- 

 script and in the proof-reading of the book has been taken, 

 it cannot be expected that errors have been entirely avoided, 

 and readers discovering any such will confer a favor by 

 communicating them to the author. 



F. W. WOLL. 

 Madison, Wis., December, 1899. 



