RENAL EFFICIENCY AND BLOOD-PRESSURE 163 



one hour, two hours, three hours after the administration of the 15 grm. urea. The 

 quantity, urea concentration, specific gravity, presence of albumin, examination 

 of the centrifugalized deposit, were noted. The patient was then allowed to resume 

 his normal diet, and in the course of the afternoon, between 2 p.m. and 3 p.m., 

 the exhibition of liquor trinitrini Cl)ij three-hourly for the succeeding twenty-four 

 hours was commenced. 



In one series of cases referred to in Table VI, erythrol tetranitrate was used 

 as a vasodilator ; the general effects are seen to be similar. On the second day 

 of examination, i. e. about eighteen hours after the administration of the first dose 

 of trinitrinum, the same examinations of the blood and urine were carried out at 

 approximately the same time and with the same routine. 



After the completion of the second urea test no further trinitrinum was given. 

 On the third day, the blood and urine were examined again as before. 



Blood-pressure readings, both systolic and diastolic, pulse-rates, and respira- 

 tion-rates were observed each day during the forenoon in practically every case. 

 Full clinical notes were also made. No difficulty was experienced in getting 

 blood from the same vein on successive days, so that the other arm was always 

 used for blood-pressure readings. 



In Case 1 no liquor trinitrini was employed, as a venesection was decided 

 on by the medical officer in charge of the case. No untoward effects due 

 to the liquor trinitrini were observed except in one or two cases. One case 

 (No. 2) complained of flushes and palpitation, while another case (No. 7) did 

 not show a lowered blood-pressure until the liquor trinitrini had been 

 administered in two-minim doses three-hourly for forty-eight hours, and three- 

 minim doses four-hourly for the succeeding twenty-four hours. This caused 

 the patient to vomit and to suffer from headache, palpitation, &c., while his 

 blood-pressure fell considerably on the third day of the administration of the 

 liquor trinitrini. 



One or two cases showed a slight increase in the urea and non-protein 

 nitrogen of the blood while under the influence of the vasodilator. In order to 

 make certain that this increase in the blood urea was not due to diminished 

 power of the kidney, while the blood-pressure was lowered, to excrete the 

 increased amount in the blood due to the giving of the initial dose of urea 

 on the preceding day, the above routine was slightly altered as follows in a series 

 of cases : 



1st day : Routine examination of blood, urine, &c. 



2nd day : Administration of the trinitrinum begun. 



3rd day : Routine examination of blood, urine, &c. Trinitrinum stopped 



after completion of the urea concentration test. 

 4th day : Nil. 



5th day : Routine examination of blood, urine, &c. 



In all cases patients were kept in bed throughout the three- or five-day periods 

 of examination to obviate as far as possible the influence of variations in external 

 temperature, &c., on diuresis. 



