THE VITAL PHENOMENA OF BACTERIA. 8 1 



than phenol. Phenol is, however, a very re- 

 active body, so that the exception is only ap- 

 parent. 



Regarding isomeric bodies the chemically 

 more reactive might be supposed to be the more 

 poisonous. For example, the isonitriles or 

 isocyanides or carbylamine whose base is a 



hypothetical isocyanic acid or isoprussic acid 



v 

 of the formula CN.H (more accurately C=N-H, 



HI 



or, according to others, C=N-H) ought to be 

 more poisonous because more reactive than 

 the nitriles or cyanides whose base is the 



prussic acid of the formula H.CN (more accu- 



iii 



rately N=C-H). The mustard oils which are 

 derived from the hypothetical iso-sulpho- 

 cyanic acid (S. CN. H) are not poisonous, the 

 sulpho-cyanates which are derived from the 

 sulpho-cyanic acid (S. H. CN) are poisonous. 

 One of the most potent poisons known, prussic 

 acid (H. CN), or formic acid nitrile, belongs to 

 the nitriles. It is, to be sure, very reactive, 

 so that the foregoing exceptions are, perhaps, 

 only apparent. These examples have been 

 chosen in order to show that we are but just 

 entering upon a rigorous scientific conception 

 of the nature of these questions, and are still 

 at the beginning of the development of laws. 



