TO FIRST EDITION. 



WITHIN the past ten years much has Ixvn said and 

 written concerning tin 1 basic substances forim-d during the 

 putrefaction of organic matter, and those which are pro- 

 duced by the normal tissue-changes in the living organism. 

 Many investigators have given their whole time and atten- 

 tion to the study of these substances, and important discov- 

 eries have been made and much light has been thrown upon 

 what have heretofore been considered problems in medical 

 science. To collect, arrange, and systematixe the facts 

 concern inn; j Romanies and leiiconia'ines has been our first 

 olijcct. Although many short essays, some of them of 

 -iv. -it value, have been written with the above-mentioned 

 object in view, the present work may he regarded as tin- 

 first attempt to make this collation embrace everything of 

 importance on this subject. In endeavoring to accomplish 

 this object we have met with many difficulties. The original 

 reports of the various investigators arc scattered through 

 the pages of medical and Scientific journals, trail-actions of 

 societies, monograph-, -o\ernment reports, etc. However, 

 with few exception- we have been able to obtain the original 



