W.G. Lyle and L. J. Curtman 3 
off and the alcohol removed from the solution by distillation. 
The residue in the flask was treated with 20 gm. of KOH dissolved 
in water, diluted considerably, and precipitated as before with 
about 20 cc. of glacial acetic acid. The precipitate was filtered 
off and dried as described above, after which it was ground and 
kept in a desiccator. The weight of the material finally obtained 
was 30.3 gm. representing a yield of 60 per cent. The time re- 
quired to make this preparation was 4 hours, the distillation of 
- the alcohol being the most time-consuming of all the operations. 
A solution containing 1 gm. of this preparation in 60 cc. of 95 
per cent alcohol was prepared, kept in a glass-stoppered bottle — 
of colorless glass, and its sensitiveness determined from time to 
time with a standard solution of blood. No appreciable difference 
in sensitiveness was observed at the end of several weeks. There 
is therefore no need for freshly preparing the solutionin making 
the test. 
Procedure for the Examination of Stools for Occult Blood. 
After considerable experimentation, the following procedure 
was adopted. Approximately 10 gm. of the stool are transferred 
to a beaker, 25 cc. of distilled water are added, and the mixture 
is stirred until of uniform consistency. Over a low flame, the 
mixture is heated with constant stirring to boiling and kept at 
the boiling temperature for several minutes. After cooling, one- 
half of the mixture is transferred to a glass-stoppered bottle of 
80. cc. capacity, 5 cc. of Merck’s reagent glacial acetic acid and 
25 cc. of ether are added, and the mixture is thoroughly shaken and 
allowed to stand for several minutes. In a test-tube, 2 cc. of 
the ether extract are treated with 0.5 cc. (1 : 60) of the prepara- 
tion described in this paper and finally one to five drops of 30 per 
cent Merck’s reagent perhydrol are added slowly from a pipette. 
A decided green, light or dark blue, or purple color indicates the 
presence of blood in quantity to be of clinical significance. Our 
experiments confirmed those of Buckmaster who first pointed 
out that boiling the blood was without influence on the test with 
guaiaconic acid. 
