Dk. jMitchell on the Physiological Actions of Spartine and Scoparine. 177 



transparent, and acid, their urine, which is nominally opalescent and 

 alkaline. In its action upon the kidneys in man, it appears merely to 

 increase the secretion of water. In the case of A. B., the amount of 

 solids thrown oflF daily in the urine was, on an average, 827 grains; and 

 while under the stimulus of scoparine, the amount of solids averaged 826 

 grains ; thus showing the singular fact, that between the periods when the 

 whole excretion averaged 34 oz., and that when the whole averaged 

 80 oz., there was only the difference in the average of contained solids of 

 1 grain. These results are so very close, that they almost seem acci- 

 dental ; but it must be remembered, that in both cases the averages are 

 struck from a long train of experiments, the only safe method of conduct- 

 ing such researches as the present. As far as possible, too, I had made 

 all the conditions in the two cases identical. We thus find the absolute 

 amount of salts in the urine to be unaffected, while the ac^ueous portion is 

 more than doubled. I ascertained, too, in a rough manner, that these 

 salts were in the relative proportions of health. 



Now it seems somewhat astonishing that a body possessing such 

 indefinite and negative properties as scoparine, should have a diuretic 

 action, or indeed any marked action at all on the animal economy. 

 And it at once becomes a point of interest to ascertain the channel 

 by which it stimulates the kidneys to an increase of their secretion. 

 About the period of conducting these researches, I happened to observe, 

 in giving gallic acid in pretty large doses, for the purpose of arresting 

 hjeraorrhage from the lungs, that it exerted a dim-etic action. A 

 few experiments and additional observations determined the question. 

 In examining the urine of these cases, I detected, without difficulty, the 

 presence of gallic acid itself. The same thing was done in the milk of 

 the mother, and the urine of the child at the breast. I believe this is 

 the first notice of such a property possessed by gallic acid, although Dr. 

 Christison recently told me that such has of late been observed in the 

 Edinburgh Infirmary. I make allusion to it, however, with reference to 

 its mode of action. This substance appears to operate as a direct 

 stimulant to the secreting vessels of the kidney, being taken into the 

 current of the circulation, and carried without undergoing any decom- 

 position in transiho to the urinary organs. Now to this class of diuretics, 

 Pereira refers broom; but / could in no case detect any evidence of 

 the existence of scoparine in the urine. I therefore felt inclined rather 

 to suppose that being partially acted on by the digestive organs, some of 

 its component parts thus eliminated had been conveyed to the kidneys, 

 and that they had thus been stimulated to increased action, or, that this 

 substance had acted primarily on the stomach, and that its action on the 

 urinary organs was a secondary one, communicated by sympathy. Find- 

 ing this diuretic property in both gallic acid and scoparine, I thought it 

 possible that some of the other yellow colouring principles might be 

 similarly endowed. And such observations as I made were affirmative of 

 this expectation, so that we have a class of bodies somewhat analogous in 



