168 QUARTERLY JOURNAL OF MEDICINE 



Methods : (1) Urea. The urease method of Van Slyke as modified by 

 MacLean (10) was employed. 



(2) Non-protein nitrogen. For this estimation the adaptation of Folin's 

 method described by MacLean (11) was used. 



(3) Percentage of urea in the urine. The hypobromite method was used, the 

 volume of nitrogen evolved being measured within one minute after shaking, and 

 the equivalent percentage of urea read off from tables compiled by means of 

 estimations carried out on various specimens of urine by the urease method. 



(4) Systolic and diastolic blood-pressure. The auscultatory method was 

 used throughout. The patient was kept in the semi-recumbent position, and the 

 same upper arm was employed for the compression armlet in all observations, an 

 Oliver auditory tambour being used. The systolic blood-pressure index was 

 always checked by simultaneous- employment of the tactile method, recommended 

 as a routine method a number of years ago by Mac William and Melvin (12). The 

 diastolic pressure was taken as usual as the beginning of the fourth phase. In 

 no cases were first readings relied on ; the readings were repeated in each case 

 several times during the course of half an hour till a constant level was obtained 

 as shown by both auditory and tactile indices. During this time, variations in 

 the pulse and respiration were noted. Each reading was made quickly, so as to 

 avoid prolonged compression by the armlet, undue congestion of the arm, &c. The 

 pressure was estimated twice in each three-hourly period, once before the middle 

 of each period and another in its latter part. Such a distribution of the estima- 

 tions tends to reduce possible disturbance of values due to any variations of 

 pressure that may occur within the period, and give a nearer approach to the 

 average level of pressure. Substantial lowering of pressure shows a general 

 parallelism with the reduction in the volume of urine excreted during the 

 same period. 



The chief results obtained are stated in Table I on pp. 416-19, dealing with 

 pathological cases of high blood-pressure, some with and others without kidney 

 lesions, cardiovascular changes of various kinds being usually present as noted in 

 the table. The patients were mostly in middle or advanced life — sixteen males 

 and five females. Their general condition varied much. 



The dietetic conditions were similar in almost all cases — the usual infirmary 

 full diet. The urea test was completed and blood samples taken in the morning, 

 no food or drink having been taken for at least five to six hours previously. 



Preliminary Conclusions from the Results obtained in the Pathological Cases in 

 Table I under the Influence of the Vasodilator Drug. 



1. Effects on the blood urea and non-'protein nitrogen. The blood urea 

 figure and the non-protein nitrogen figure expressed in milligrams per 100 c.c. 

 blood were not affected to any extent except in Cases 4, 7, and 8, in which a decided 

 rise occurred. The reasons for the rise in Cases 4 and 8 are quite definite. In 



