1.
Uranium and
cantharidin, in the smallest doses capable of producing a distinct
nephritis, tend to increase the elimination of
nitrogen, probably by stimulating tissue katabolism. 2.
Uranium,
cantharidin, and
potassium chromate, in larger doses, impair the power of the kidney to eliminate
nitrogen; but this may not be evident unless the animal is on a high
nitrogen diet, and the impairment, when due to
potassium chromate, may not persist more than a day. 3. Small doses of
uranium and of
cantharidin cause a transient increase of
chloride elimination which corresponds in a general way to the excess of diuresis. 4. Large doses of
uranium and of
chromate cause a fall, usually transient, in the
chloride elimination. The
chloride elimination may, however, be diminished forty per cent. for twenty-four hours without evidences of intoxication (
vomiting). 5. The anatomic appearance of the kidney varies somewhat with the
poison used and greatly with the period of survival after administration of the
poison, but bears no definite relation to the
nitrogen, chloride, or phenolsulphonephthalein elimination; marked anatomic alteration is compatible with normal elimination of all these substances and with freedom from symptoms of intoxication (
vomiting). 6. The decrease in the elimination of phenolsulphonephthalein, which occurs in
uranium,
chromate, and
cantharidin nephritides, and which, in a general way, is proportional to the dose of the
poison, bears no constant relation to the changes in the
nitrogen or
chloride elimination. 7. A marked decrease in the elimination of the phenolsulphonephthalein occurs synchronously, as a rule, with the onset of the symptoms of intoxication (
vomiting), and therefore the phenolsulphonephthalein test would seem to be a better
indicator of the ability of the kidney to eliminate the toxic substance responsible for the symptoms of
renal insufficiency than are either the anatomic changes or the elimination of total
nitrogen or of
chlorides.