191^^ Action of Various Diuretics 37 



tlie dog which is sufficient to induce the desired changes in the 

 kidney without the undesirable gastro-intestinal complications 

 has been found to be 6.7 mgs. per kilogram. This is the dose 

 of uranium which has been constantly employed in all of the 

 experiments. 



Only animals in apparently perfect health were selected for 

 the experiments. They were placed in metabolism cages and 

 given daily by a stomach tube a known and constant quantity 

 of water. The diet consisted of bread and uncooked meat. 



The urine was collected at 4.30 p. m. each day and examined 

 qualitatively for albumen, sugar and acetone, and quantitatively 

 for sugar. In making both the qualitative and quantitative 

 sugar determinations, Benedict's (2) reagents were uniformly 

 employed, for the reason that these solutions allow of more 

 delicate determinations and do not deteriorate upon standing. 

 'No preservative was used in the urine. 



These observations were made for three days prior to the ad- 

 ministration of the uranium. On the third day the first uranium 

 injection was made and repeated at the same time on the fourth 

 day, the experiment being performed on the fifth day that the 

 animal had been under observation. Such a routine is neces- 

 sary, for the changes in the urine, especially the output of glu- 

 cose, are influenced to some extent by the time which has elapsed 

 following the uranium injections. 



As a result of the foregoing study of the urine the use of an 

 animal with a naturally acquired nephritis was excluded, N^one 

 of the animals prior to the use of the uranium showed the pres- 

 ence in the urine of either glucose or acetone. 



The diuretic substances which have been employed in these 

 experiments include those which were used with the first series 

 of animals; and, in addition, various salts which were used 

 in solutions isotonic with 0.9 per cent and 2 per cent sodium 

 chloride. 



The osmotic pressure of some of the salts which have been 

 employed has never been accurately measure. This, therefore, 

 introduces an element of error into the calculations, which were 

 conducted in order to obtain solutions of these salts isotonic 



