38 Journal of the Mitchell Society [June 



with 0.9 per cent and 2 per cent sodium chloride. The calcu- 

 lations were made for solutions at 37.5 °C. and at this tempera- 

 ture the solutions were introduced into the animals. For these 

 calculations, I am indebted to Dr. J. E. Mills, of the University 

 of South Carolina. 



The following solutions have been employed in the study of 

 the response of the nephritic kidney to diuretic substances : 



Caffeine 1 to 2 of a 1 per cent soution per kilogram 



Theobromine 1 to 2 of a 1 per cent solution per kilogram 



Digitalin 0.5 to Img. per kilogram 



Sodium chloride solution, 0.9 per cent 5 to 10 cc. per kilogram 



Sodium chloride solution, 2 per cent 5 to 10 cc. per kilogram 



Sodium carbonate, 0.9 per cent 5 to 10 cc. per kilogram 



Sodium carbonate, 2 per cent 5 to 10 cc. per kilogram 



Sodium sulphate, 0.9 per cent 5 to 10 cc. per kilogram 



Lithium chloride, 0.9 per cent 5 to 10 cc. per kilogram 



THE effect of URANIUM NITRATE ON THE OUTPUT AND COMPO- 

 SITION OF THE URINE IN YOUNG AND IN FULL 

 GROWN ANIMALS 



As has been previously stated, the present series of experi- 

 ments serve not only for a study of the efficiency of various diu- 

 retic substances, but they also serve to demonstrate the differ- 

 ence in the response of animals of different ages to the same 

 quantity of a toxic substance, such as uranium. The differences 

 here referred to are those which are manifested in the total out- 

 put of urine and in the composition of the urine. 



During the course of this paper the animals referred to as 

 " young," are animals not over one and a half years old ; the 

 " adult " animals are those varying in age between one and a 

 half and six years ; while the old animals are certainly over six 

 years old. The classification is, of course, a more or less arbi- 

 trary one, though it is based to some extent upon a knowledge of 

 the average life of the dog. 



Falling in the group of young animals are eight dogs. Four 

 of these animals were from the same litter, and at the time of 

 the experiments were between four and a half and five months 

 old. Two other animals were three months and three weeks old ; 



