514< Dr. Hofmann on the Metamorphoses of Indigo* 



Dichloraniline . • \_ q X^-^\n 



Amachlophenise .J ~ '^L^'aJ 



Trichloraniline . • 1 _p -r^4\N 



Amachlophenose . J ~ ^^\Clgj 



Substitution of the hydrogen by chlorine and bromine. 



Chlorodibromaniline I 

 Amachlobrophenose [ " 



Substitution of the hydrogen by bromine. 



BromaniUne . . • 1 c^ JMn 



Amabrophenese • • J L^^ J 



Dibromaniline . • 1 _ p / ^^ T XT 

 Araabrophenise . . j ~ ^^i^BrgJ 

 Tribromaniline . • \_ p X^4\n 

 Amabrophenose . . J "" ^^ L^^'s J 



We now return to the question, can chlorine play the part 

 of hydrogen in organic compounds ? 



The isatine group is perhaps quite capable of affording 

 some explanation of this question. 



In isatine we have a body which, by the action of chlorine, 

 loses one or more equivalents of hydrogen, which are replaced 

 by the acting substance. These three compounds, isatine, 

 chlorisatine and dichlorisatine, possess the same chemical and 

 physical properties. By the substitution of chlorine for hy- 

 drogen the character of isatine has not been changed. Isatine, 

 chlorisatine and dichlorisatine, by the action of other agents, 

 suffered similar changes. By treatment with sulphuret of 

 ammonium we see these three bodies assuming one equivalent 

 of hydrogen and changing into isatyd, chlorisatyd and dichlo- 

 risatyd. By proper treatment with sulphuretted hydrogen the 

 whole or part of the oxygen can be eliminated and replaced 

 by sulphur. In contact with alkaline sulphates the sulpho- 

 isatinic and chlorisatinic salts are formed ; peculiar com- 

 pounds, in which the sulphurous acid is united in a singular 

 manner with the organic substance. The behaviour of isatine 

 and chlorisatine to ammonia and alkalies is also similar : par- 

 ticularly towards the latter the analogy in their action is in the 

 liighest degree characteristic. At the ordinary temperature 

 they unite directly with the alkalies, but at a boiling lieat 

 they change into isatinic and chlorisatinic acid, whose strict 

 analogy in all these salts never fails. Finally, by fusion with 

 hydrate of potash, we see isatine converted into aniline ; when 

 chlorisatine is treated in the same manner, still under con- 

 ditions which certainly are favourable to fix the chlorine, this 



