URIC ACID. 595 
uric acid after a meal is by qo humus marked, unless the food taken contains 
nuclein. On a diet composed, for instance, of egg albumin, the rise was very- 
small, while during the digestion of non-nitrogenous diet the output of uric 
acid was even diminished. Camerer holds, therefore, that digestive leuco- 
cytosis cannot be the cause of post-prandial increase, but only the actual 
ingestion of nuclein-, and his results would suggest that we must answer the 
question in the previous paragraph in the affirmative, and recognise that 
the excretion of uric acid is not increased by the ingestion of ordinary 
proteids. 
if this be confirmed, we must for the future attach no importance to the 
urea : uric acid ratio : and when we wish to eliminate mere dietetic effects 
from our study of other specific variations in the urinary uric acid (when, for 
instance, we are endeavouring to ascertain if retention is occurring in disease, 
or whether a certain drug is promoting elimination), Ave must do this by 
controlling the ingestion of nucleins during the experiments. 
It should be understood, however, that in spite of much labour spent 
upon the problem, our knowledge of the relation of urinary uric acid to 
diet is scarcely yet upon a firm foundation, and contradictory statements 
will be found in the literature. Future investigators may have to face 
yet another difficulty, if it be true, as Weintraud 1 affirms, that a true 
excretion of uric acid may occur through the walls of the intestine. 
One fact is abundantly certain — that great individual differences 
exist in uric acid excretion. In spite of all that has been said above, it 
is found that, with the ordinary regularity of habits and diet customary 
in civilised life, the uric acid output (when the whole twenty-four hours' 
excretion is dealt with), and even its relation to urea, will remain fairly 
constant in any given individual: whereas, when different individuals 
are compared, much greater differences are seen. Before we can say 
with certainty what constitutes a pathological or exceptional condition 
in any case, we must know the normal behaviour of the particular 
organisation in question (Salkowskj ). 
The ratio borne to urea may vary in different healthy individuals 
from 1 : 25 to 1 : 50 ; the proportion most commonly found being from 
about 1 :35 or 1 :40. 
(b) Variations apart from diet. — It is a well-established fact that 
in newly-born children the uric acid excretion bears a high proportion 
to the body weight, and also to the other nitrogenous constituents of 
the urine. In the first few days of life 7'8 per cent, of the urinary 
nitrogen may be in the form of uric acid. 2 
The absolute amount is increased by excessive exercise and 
diminished by rest. With regard to drugs, the action of alkalies is 
still disputed. It is possible that an isolated dose may temporarily 
accelerate excretion; but, according to Spilker and Salkowski, 3 continued 
administration diminishes it. There is certainly no foundation for the 
statements of Haig, that the excretion of uric acid varies inversely as 
the acidity of the urine. 4 Salicylates undoubtedly increase the amount 
in the urine. Pilocarpine produces an increase, possibly from the 
leucocytosis which follows its use. Pathologically, there is increase in 
1 Chera. Centr.-BL, Leipzig, 1895, Bd. ii. S. 310. 
2 Hofmeier, Virchow's Archiv, 1882, Bd. lxxxix. S. 493. 
3 Ibid., 1889, Bd. cxvii. S. 570. 
4 Cf. Herringham and Davies, also Herringham and Groves, Jov.rn. Physiol., Cambridge 
and London, 1891, vol. xii. pp. 475 and 478. 
