6 Occult Blood in Stools 
sufficient of the pills to make one dose. Negative results were 
obtained with the following: American store cheese, custard, milk, 
prunes, oatmeal, farina, wheatena, bread (white), rice, egg, ice 
cream, condensed milk, compound C pills, A, B, and §, and A, B, 
and P, and laxative pills. A positive test was given by meat soup. 
Application of the Method to Hospital Cases. 
The method described in this paper was used in the examination 
of over 500 stools to be tested for occult blood with satisfactory 
results. Before carrying out the test, the patient was kept for 
at least 2 days on a meat-free and soup-free diet. Although a 
light green color indicated small quantities of blood, for clinical 
purposes, we chose to report such cases as doubtful and considered 
only those cases positive in which a dark green or blue color was 
obtained. 
SUMMARY. 
A new procedure for the detection of occult blood in stools is 
proposed, the chief features. of which are: 
1. The use of a new preparation derived from gum guaiac, 
which possesses the merit of being both stable and sensitive. 
2. Specific directions for the preparation of the ether extract. 
3. The use of perhydrol. 
The method was applied to the examination of over 500 speci- 
mens with satisfactory results. 
