A NEW METHOD FOR THE DETECTION OF OCCULT 
BLOOD IN STOOLS. 
By WILLIAM G. LYLE anp LOUIS J. CURTMAN. 
(From the Harriman Research Laboratory, The Roosevelt Hospital, New York.) 
(Received for publication, November 5, 1917.) 
The finding of cecult blood in stools is of great importance in 
the diagnosis of ulcer and cancer of the stomach. However, the 
usual chemical methods are so unreliable in their results that they 
are at present discredited by many surgeons and internists. A 
review of the literature of this subject shows not only that the 
number of reagents proposed is very large, but that there also 
exists a considerable number of procedures for the use of these 
reagents. The two most widely used are gum guaiac and ben- 
zidine. The phenolphthalein reagent is difficult to prepare and 
moreover is entirely too sensitive for ordinary use. In a previous 
paper! we have shown how the benzidine reagent may give erron- 
eous results unless great care is exercised in cleaning all the ap- 
paratus as well as in the use of reagents of definite concentrations. 
In the routine examination of stools we have found it difficult to 
get good controls with benzidine; moreover, it is too sensitive. 
An alcoholic solution of gum guaiac possesses the following dis- 
advantages: (1) Not being of fixed composition or purity, a solu- 
tion of definite concentration cannot be readily prepared. (2) 
Gums from different sources vary greatly in their sensitiveness 
as well as in the stability of the blue compound formed.? (3) 
For the best results, solutions must be freshly prepared. 
1 Lyle, W. G., Curtman, L. J., and Marshall, J. T. W., J. Biol. Chem., 
1914, xix, 445. 
2 In this connection the following Cee rent will be of interest. Three 
specimens of gum guaiac purchased from different dealers were ground and 
separately dissolved in 95 per cent alcohol in the proportion of 1:60. 0.5 ce. 
of each of these solutions was added to 2 ce. of an acetic acid-ether extract 
of a stool and treated with perhydrol. The first did not give a positive 
test, the second gave only a faint test, while the third yielded a good blue 
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THE JOURNAL OF BIOLOGICAL CHEMISTRY, VOL. XXXIII, NO. 1 
