122 
DETECTION OP POISON IN THE URINE. 
cent state of the urine, by the administration of the mineral 
acids, was no proof that these acids did not pass off by the 
urine ; for in nearly all cases of alkaline urine it became 
alkaline after its secretion, from the decomposition of the 
urea, and such an amount of ammonia was produced in 
this way as it would be almost impossible to neutralise by 
any quantity of mineral acid which could be safely admi- 
nistered as a medicine. 
Dr. Letheby observed, that the remarks of Dr. Snow had 
rendered it unnecessary for him to answer Dr. Bird, as far 
as regarded the detection of the mineral acids in the urine. 
He might observe, however, that in these experiments, the 
urine had been in the normal state, when, in fact, it was 
slightly acid, not when the phosphates were thrown out, as 
as these would, of course, neutralise the acid given by the 
stomach. After giving these acids, the urine became more 
acid, the acids being formed either in combination with 
their base or not : but this did not affect the question. He 
could not explain, any more than could Dr. Bird, in what 
way diuretics acted in cases of poisoning, but he had merely 
mentioned the facts which he had observed. 
Dr. Copland, in 1821, had published a memoir on chemi- 
cal remedies, and their mode of elimination from the sys- 
tem; and, in 1824. had experimented with the mineral acids 
and camphor. These experiments would be found in a 
forthcoming number of his u Dictionary." One circum- 
stance which he had noticed in relation to these acids was, 
that the sulphuric was more easily detected than either the 
nitric or muriatic acids ; but this he had supposed, at the 
time, to arise from the circumstance of the two latter acids 
being decomposed. He had found the same difficulty as 
had the author, in detecting vegetable substances in the 
urine, as turpentine, camphor, and other volatile substances 
were sooner carried off by the mucous membrane of the 
respiratory organs, than by that of the urinary. The depu- 
rating power of the kidneys had not been overlooked by 
