154 



Scientific Proceedings (59). 



possessing uricase, and hence in this property the anthropoids 

 stand closer to man than to the monkeys, as they are also said 

 to do in serological reactions. We have found a marsupial, the 

 opossum, to have uricase, xanthine oxidase, guanase but no 

 adenase. In respect to uric acid destruction our results agree 

 perfectly with the urinary analyses of Hunter and others. 



96 (913) 



A quantitative application of the Abderhalden serum test. 

 By Donald D. Van Slyke and Miriam Vinograd. 



[From the Hospital of the Rockefeller Institute for Medical Research, 



New York.] 



The Abderhalden serum test can be greatly simplified, made 

 quantitative, and the sensitiveness increased about thirty-fold 

 compared with the dialysis test, by utilizing the nitrous acid 

 method to detect proteolysis. The technique is the following: 

 2 c.c. of serum are digested with o. 1 gram of dried substrate (tissue 

 prepared according to Abderhalden's directions and dried quickly 

 at 0.5 mm.), or, as nearly as can be estimated 0.4 gram of undried 

 substrate. After the digestion is complete, 3 c.c. of water are 

 added. The solution is then centrifugated, and 2 c.c. used for 

 amino nitrogen determination in the micro-apparatus, 0.5 c.c. of 

 caprylic alcohol being used to avoid foaming, and the reaction 

 being run four minutes. Control analyses are run under the same 

 conditions with serum that has been digested with normal tissue, 

 and with no tissue. The amino method will detect one fourth 

 the concentration of a-NH 2 that is apparent by the ninhydrin 

 reaction, and the serum is diluted only one eighth as much in the 

 above procedure as in the dialysis test, so that the sensitiveness is 

 increased about thirty-fold. In spite of this, our results have 

 been absolutely negative with the Rous chicken sarcomas Nos. 1 

 and 2, even when serum tested was from the chicken furnishing 

 the tissue substrate. The results do not, of course, bear on the 

 validity of the test in human cases. We are about to test the 

 method in human cancer and in pregnancy. The work on chicken 

 tumors has been possible as a result of the cordial cooperation of 

 Dr. Rous and Dr. Lange. 



