266 
MISCELLANY. 
and indigo. This acid has nearly the same radical as indigo, and is re- 
presented by KT? 0\ 
Picric Acid. — This is the last product of the action of nitric acid upon 
indigo, most generally designated by the name of Bitter of Wetter. It 
is composed, according to Dumas, of C^-i Yi^ AZ^ O^^. 
M. Dumas thinks that an oxide of azote enters into its constitution. 
Rid. 
Physiological operation of Indigo. — In almost all patients, the use of 
indigo is succeeded first by squeamishness and vomiting, though the sub- 
stance itself be tasteless and inodorous. The violence of the emetic ef- 
forts appears to be regulated by the individual irritability of the gastric 
nerves of the patients. Females vomit more readily than males. The 
vomiting is at first continuous, that is, during the continued use of the 
agent, and often so violent that the indigo must be given up ; but after 
several days it ceases. It has otherwise the peculiarity that the contrac- 
tion of the abdominal muscles and the diaphragm is much less violent, 
and the debility is less considerable than after vomiting induced by other 
means. The contents of the stomach present nothing unusual, even in 
respect to taste, only they are of a very dark blue colour, and the fluid is 
intimately mixed with the indigo, from which it may be inferred that 
the gastric juice contributes very much to the digestion of the indigo. 
Diarrhoea, the second physiological effect of indigo, takes place in ge- 
neral first when the vomiting ceases ; yet from this many patients remain 
altogether exempt. In general, diarrhcea, when once commenced, conti- 
nues as long as the patients take the indigo, and increases in intensity 
during the continued use of the remedy. The motions are generally soft, 
semifluid, and of a dark blue-black colour. The vomiting and diarrh(ea 
are frequently accompanied with slight colicky pains in the stomach and 
bowels, which, however, may be so violent as to require the indigo to be 
given up. Those patients who are exempt from vomiting, appear to be 
attacked with more violent colicky symptoms. By the continued diar- 
rhoea there is formed a species of gastrosis (irritation of the mucous 
membrane of the stomach and bowels,) with a loss of appetite, head- 
ache, and giddiness, and sometimes the sense of dazzling lights in the 
eyes. 
The third physiological operation of indigo is seen in the urinary 
secretion. The urine assumes a dark violet colour, deepest in the 
morning. On the quantity of the urine the agent seems to exercise no 
influence. 
Dr, Roth did not observe colouration of the sweat. But it is remarkablei 
that one patient, after the use of indigo for several weeks, fell often into 
slight convulsions, similar to those which ensue on the employment of the 
nitrate of strychnia. 
