VI PREFACE TO THE FOURTH EDITION 



In the appendix a new section has been added on the chemical blood 

 examinations, and in that on insecticides the recent views as to the best 

 methods of destroying lice to control the spread of typhus fever and 

 relapsing fever have been incorporated. 



There has also been added to the appendix a section dealing with 

 anatomical and physiological normals to furnish ready reference for 

 work in the pathological or chemical laboratory. 



Among the tests more recently accepted as of practical value and 

 incorporated in this edition may be mentioned the following: Schick 

 test for diphtheria immunity, tests for recognition of acidosis, tests 

 for efficiency in renal functioning, PetrofTs method for culturing tuber- 

 cle bacilli, Wolff and Junghans' test for gastric carcinoma, Bronfen- 

 brenner's modification of Abderhalden's technic, tests as applied to 

 the duodenal fluid, Lange's colloidal gold test for general paresis, 

 Fontana's spirochete staining technic, Gluzinski's gastric carcinoma 

 test, and many others. 



There have also been many new illustrations of animal parasites 

 substituted for those in the third edition which did not appear to have 

 sufficient teaching value. 



E. R. S. 



