VARIATIONS IN THE ACIDITY OF THE URINE. 241 
the ground that all his determinations were reckoned for 
1000 parts instead of per hour. This objection would have 
had weight if the density of each specimen had not been 
recorded. Great dilution of the urine from abundant 
potation would no doubt reduce the degree of acidity per 
1000 parts, even when the quantity of acid discharged per 
hour remained constaut; but this source of fallacy was 
guarded against in the observations of Dr. Jones by taking 
the density of the secretion — this being a sufficient mea- 
sure of its concentration. Dr. Vogel goes on to say: 
“Researches undertaken partly by myself, and partly 
by others under my direction, showed uniformly that the 
greatest quantity of acid secreted per hour by the kidneys 
occurred during the night, the least in the forenoon, while 
a medium quantity was discharged in the afternoon after 
the principal meal. These results therefore are unfavour- 
able to the conclusions of Dr. Bence Jones, but do not tell 
conclusively against them, inasmuch as other circum- 
stances may have had an influence on the amount of 
acidity.” 
Dr. Sellers, in the Edinburgh Medical Journal for Janu- 
ary 1859, states that in a good many trials he has not 
been able to satisfy himself “that the rule, as laid down 
by Dr. B. Jones, is generally applicable in Edinburgh ; 
certainly not to the extent that the urine loses entirely its 
acid character, or that it becomes alkaline.” Nevertheless 
it has seemed to him “that the variations in the degree of 
its acidity are in some measure governed by the existing 
states of the stomach.” 
Dr. Delavaud (Gaz. Médicale, 1851, No. 44) found the 
urine becoming neutral or alkaline after breakfast, but not 
after dinner. 
Seeing this discrepancy in the results obtained by difler- 
ent observers, it seemed not undesirable to seek additional 
and exact information on the effect of food on the reaction 
