Studies of Liver Function. Benzoate Administration and Hippuric Acid Synthesis

Much work has been done in an effort to understand the complex function of the liver and considerable information of value has been obtained. It is fair to say, however, that the estimation of functional capacity of the liver cannot as yet be made with any convincing accuracy. We have reason to believe that the liver has a very large factor of safety-that it can tolerate an extensive injury and yet carry on its essential body functions. Any satisfactory functional test must include, therefore, some factor of strain or load which can measure the upper limits as well as the lower limits of liver function. It is certainly possible that some of the many functions of then liver may be seriously impaired while others, perhaps of more fundamental significance, are not seriously disturbed. This may apply to acute as well as chronic disease conditions. Probably the liver function test which is of most value in physiological experiments is given by the use of phenoltetrachlorphthalein as described by Whipple, Peightal, and Clark (1). This drug is given ihtravenously and eliminated promptly in the bile. It can readily be recovered from the feces and accurately estimated. This functional test shows a great impairment after extensive liver injury by chloroform or phosphorus, but a serious objection is at once obvious if any abnormalities of bile secretion are present. With complete biliary obstruction obviously the test is of little value and with chronic inflammation of the bile passages, we find a marked lowering in output of the phenoltetrachlorphthalein-for example in long standing biliary fistulas. For clinical use, therefore, this test has very serious