PREFACE. 



The authors desire to express their multiple obligations to the Smithsonian 

 Institution. They have to thank the Army Medical Library for the valuable 

 Bibliography appended to this essay. With that to be found in Dr. Weir Mitchell's 

 former essay, it completes the list of such knowledge up to January, 1885. They 

 desire also to thank Her Britannic Majesty's Indian Government for help in secur- 

 ing Indian serpent poisons. Among individuals they owe to no one so deep a debt 

 as to Vincent Richards, Esq., of Goalundo, British India. Without his untiring 

 aid the authors feel that it would have been impossible to have extended their 

 inquiries beyond our native snakes. 



The excellent plates were drawn for the most part by Dr. J. Madison Taylor, 

 and thanks are due to Dr. Geo. A. Piersol's skill for the interesting micro- 

 photographs of blood-corpuscles attacked by venom. The authors are also indebted 

 to Dr. Guy Hinsdale for having made the tabulated reductions of kymographion 

 tracings. 



S. WEIR MITCHELL, 

 EDWARD T. REICHERT. 



Physiological Laboratory of the 

 University of Pennsylvania. 



(iii) 



