22 
to both normal and alcoholic animals. These experiments were per- 
formed for the most part upon guinea pigs for reasons given below.® 
Methods . — In the earlier experiments, the sulphocyanate was 
extracted from the acidified urine with ether and determined, approxi- 
mately, colorimetrically; later it was extracted with ether and deter- 
mined volumetrically. Neither method gave satisfactory results, so 
that in subsequent experiments Lang’s volumetric method was 
employed — titrating the urine with silver nitrate (this gives chlorine 
and sulphocyanate) and deducting from this the chlorine, determined 
by incinerating another portion of the urine with sodium carbonate 
and potassium nitrate. This method gave entirely satisfactory results 
with the urine of guinea pigs and usually vdth that of dogs. There 
seemed to be nothing present in the guinea pigs’ urine which was pre- 
cipitated by the silver nitrate except the chlorine and sulphocyanate. 
The method was not as a rule satisfactory in the case of the urine of the 
cat or rabbit, as the urine of these animals usually contained substances 
which, like chlorine and sulphocyanate, are precipitated by silver 
nitrate; the same was found to be the case vdth a few dogs. 
EXPERIMENTS ON GUINEA PIGS. 
Attention was called above to the variations in the susceptibility of 
normal mice to acetonitrile ; some of the conditions influencing this are 
the age of the animals, the character of the food, the season, etc. All of 
these factors seem to be equally important in the case of the guinea 
pig; they also seem to influence the amount of acetonitrile which is con- 
verted into sulphocyanate. The per cent of acetonitrile which is 
converted into sulphocyanate seems also in part to depend upon the 
dose. 
In the following experiments, care was taken to keep the conditions 
uniform; guinea pigs of the same age and weight were selected and 
they were then kept under identical conditions, except that to the food 
of some alcohol instead of water was added. The experiments 
were performed upon the same day, and in all cases duplicate analyses 
were made. The urine was collected and analyzed as long as it gave a 
decided reaction for sulphocyanate. The urine of the guinea pig, both 
of the normal and of those receiving alcohol, was found to be practi- 
cally free of sulphocyanate ; in some cases a faint qualitative test was 
obtained, but the amount was too small to determine. 
o These experiments were begun with Mr. E. S. Clowes, formerly assistant in the labo- 
ratory, and to whom I wish to express my thanks for his valuable assistance. It was 
our intention to extend our studies to other animals and to other conditions, but other 
work and Mr. Clowes’s resignation have prevented this. 
