248 MR. E. SCHUNCK ON THE 



night urine gave no indigo-blue, I took on the next night, 

 before going to bed, a mixture of treacle and arrowroot boiled 

 with water in as large a quantity as the stomach could bear, 

 and the effect was that the urine of the following night gave 

 a large quantity of indigo-blue. As, however, the same phe- 

 nomenon was repeated for several succeeding nights without 

 any additional quantity of food having been taken, it remained 

 uncertain to what cause it was to be attributed, though a re- 

 petition of the experiment on a second occasion gave the same 

 result. 



I have hitherto not had an opportunity of examining many 

 specimens of urine in disease. Of two samples of urine from 

 patients with albuminaria one gave a small quantity of indigo- 

 blue, the other not a trace. Several specimens of diabetic 

 urine yielded it. One of these, which I owed to the kind- 

 ness of Dr. Browne of Manchester, gave a much larger quan- 

 tity than I obtained from any other specimen of human urine. 



The urine of the horse and the cow when tried in the same 

 way as human urine gave comparatively very large quantities 

 of indigo-blue, especially that of the horse. 



I think it is highly improbable that the indigo-blue ob- 

 tained in Hassall's experiments was produced, as he supposes, 

 by the action of oxygen on the urine. Its formation was 

 without doubt due to the decomposition of the indigo-pro- 

 ducing body induced by the fermentation of the urine, the 

 indigo-blue at the moment of its formation dissolving in the 

 fermenting alkaline liquid and producing a true indigo vat, 

 from which it was gradually deposited by the action of the 

 atmospheric oxygen. When small quantities of indigo-blue 

 only are formed in any specimen of urine, fermentation is not 

 in my opinion to be recommended as a means of detecting it. 



The occurrence of the indigo-producing body as an excre- 

 tion seems to me to be due to a disproportion between the 

 oxygen absorbed by the system and the matter to be acted on 

 by it, which again may be caused either by an excessive 



