salmon pink, and on the addition of sodium hydroxide to deep pur- 
plish red. The urine of the pig which had received the o-cresolsul- 
phonphthalein differed from that which had received the phenolphtha- 
lein in this, that during the period of observation it always contained 
considerable amounts of the unaltered phthalein. whereas the urine of 
the prig which had received the phenolphthalein contained at most only 
faint traces of the phthalein and frequently none at all. On account 
of this fact it was difficult to determine whether any o-cresolsul- 
phonphthalein had entered into combination in the organism. It 
should be noted in this connection, however, that after boiling with 
hydrochloric acid any given specimen of the urine of this animal gave 
a deeper red coloration on the addition of sodium hydroxide than did 
that portion of the specimen which had not been previously boiled 
with the acid. 
SULPHOX FL L O R E SUE I X . 
On October IS. at 3.30 p. m.. 0.0500 gram of sulphonfluorescein. 
mixed with water. wa~ injected into the peritoneal cavity of a guinea 
pig weighing 335 grams. At 4. 30 p. m.. same date, the pupils of the 
eye.' of this pig when examined in a strong light showed a slight 
greenish fluorescence. The urine of this pig. passed between 7.30 p. m. 
October IS and 9 a. m. October 19, was str nglv fluorescent and salmon- 
pink in color by transmitted light. On boiling some of the urine with 
dilute hydrochloric acid and adding sodium hydroxide a stronger 
fluorescence was noticeable than ever obtained with the urine and 
sodium hydroxide alone, indicating that some of the compound had 
probably entered into combination while in the organism. 
It would mem reasonable, therefore, to conclude from these results 
that in the animal organism phenolphthalein and other phthaleins to a 
less extent enter into combination with some other substance, prob- 
ably a normal constituent of the cell, to form a complex derivative, 
which gives no color with alkali, but which is decomposed by boiling 
with dilute hydrochloric acid, yielding the phthalein itself as one of 
the products of decomposition. In other words, it seems likely that, 
under these conditions, phenolphthalein form' a conjugation product, 
probably analogous to certain glycuronates or ethereal sulphates. On 
account of the extreme slowness, however, with which it is eliminated 
from the organism when administered in the manner above described 
it has been found difficult to isolate the phenolphthalein compound in 
q nest ion . Such being the case, the following additional observations 
on the conduct of the substance occurring in the urine of guinea pigs 
that have received phenolphthalein are not without interest, and cer- 
tainly point -trongly to the notion that the phenolphthalein compound 
is a conjugated derivative. 
> ' : ’ ‘ .v'lv/i/A — Some of the urine containing the 
phenolphthalein compound was evaporated to dryness on the water 
