S88 Dr. Hofmann o?» the Met amor piloses of Indigo. 



volatile bases, all that we know is, that nicotine and coneine 

 are decomposed by the action of chlorine, but no investiga- 

 tion has as yet been made of these products of decomposi- 

 tion. 



On the other hand, there exist some accounts of the pro- 

 ducts obtained by chlorine and bromine from aniline, that 

 artificial base which has of late been met with under so many 

 different circumstances. These bodies crystallize, but they 

 no longer possess the character of basic compounds. 



I have myself communicated some observations on the 

 action of chlorine on aniline, made during an investigation of 

 the organic bases of coal-gas naphtha *. I could not at that 

 time obtain a chlorinated basic product of decomposition from 

 aniline. Besides a neutral compound, which was not pro- 

 duced in sufficient quantity for analysis, there was always 

 formed as the chief product chlorindoptinic acid (chlorophe- 

 nissic acid of Laurent), whose relation to aniline is shown by 

 the following formula ; 



Ci2 Hs, NH2+6 01+2 H0=Ci2{ "f I O + HO + NH3 + 3 CI H. 



V... y ) 1 ^ I 



Aniline. Chlorophenissic acid. 



The action of bromine on aniline, investigated by Fritzschef , 

 is much less energetic. A simple substitution of bromine 

 for hydrogen takes place, giving rise to the compound named 

 by him bromaniloid, 



Ci, H„ NH,+6 Br=Ci2|^;J,NH.2 + 3 Br H. 



* ^ ' V ^ , 



Aniline. Bromaniloid. 



But this compound too is no longer basic, but neutral, the 

 positive properties of aniline being removed by the entrance 

 of the electro-negative element into its composition. In these 

 cases the action of chlorine and bromine has evidently gone 

 too far for the aniline still to preserve its original character, 

 and it remained therefore to try in some way to regulate the 

 action of the above-named agents, so as to produce com- 

 pounds in which only one equivalent of hydrogen was replaced, 

 and which, like aniline, might possibly possess basic proper- 

 ties. 



The remarkable facility with which the derived members 

 of the phenyl family, viz. the chlorinated phenylic acid, as 

 well as bromaniloid, crystallize, made it probable that the 



* Liebig's Annctlcn, Bd. xlvii. S. 68, and Thil. Mag. S. 3, vol, xxiv. p. 1 15. 

 t Bullet. Scient. de St. Petersb., 1843, t. i. p. 30, and lAehxgi Ann., Bd. 

 xliv. S. 291. 



