VI 



Preface 



They wish to express indebtedness to the authors and publishers 

 who have so willingly given permission to use certain illustrations. 

 Especially is this acknowledgment due to Professor John Henry 

 Comstock, Dr. L. O. Howard, Dr. Graham-Smith, and Professor 

 G. H. T. Nuttall. Professor Comstock not only authorized the use 

 of departmental negatives by the late Professor M. V. Slingerland 

 (credited as M. V. S.), but generously put at their disposal the illus- 

 trations from the MANUAL FQRJTHE STUDY OP 

 the SPIDER BOOK. 

 und die Heilkunft 

 noted that on exar 

 figure relates to an 

 mania. 



CORNELL UNIVERSIT 

 January, 1915. 



