Round the Fountain

Until benzidine was taken off the market because of carcinogenic risks to those engaged in its manufacture the test most widely used was the Gregersen slide-test.'It was in general use on the Continent and in America, and was becoming more generally used in this country.It was recommended in many of the textbooks.5In general practice and in hospital side- wards there are obvious objections to tests, such as the test-tube benzidine and ortho- tolidine tests commonly employed in clinical laboratories, which may give positive results with gum-bleeding and after the eating of meats in moderate amount.Ogilvie, who was the first in this country to describe the Gregersen slide-test,8 affirmed that with it a blue or green-blue colour appearing within 30 seconds is proof of the presence of occult blood irrespective of the patient's diet, with the obvious exceptions of foods with a high blood-pigment concentration such as liver, black pudding, and bone-marrow.Now it is recognized that salicylates also should be withheld.Bockus' employs the Gregersen slide-test as a routine procedure.Benzidine is now produced under safe con- ditions of manufacture and is again on the market.Put up in waxed paper the powders will last indefinitely.The Greger- sen slide-test is cheap and simple and can be performed just as quickly as the tablet tests.Its reliability has been widely proved over the years, and it should be finding its way back into our hospital side-rooms and our consulting-rooms.-Iam, etc., Edinburgh 9. S. LIPETZ.