146 



SCIENCE 



[N. S. Vol. XLII. No. 1074 



Dr. Alice Rohde, working in my laboratory, 

 that the ammonia-yielding substances of 

 the blood can be divided into two classes by 

 the vividiffnsion apparatus; the one, com- 

 prised of diffusible substances only and 

 giving off their ammonia rapidly and com- 

 pletely on the addition of sodium carbon- 

 ate ; the other, non-diffusible and therefore 

 not escaping through our apparatus, and 

 characterized by the property of losing 

 their ammonia only very slowly on the 

 addition of sodium carbonate. 



5. By means of our method of vividiffu- 

 sion we have also found that oxyacids cir- 

 culate in the blood in noticeable propor- 

 tion. Lactic acid and /8-oxybutyric acid in 

 particular have been identified as constitu- 

 ents of the diffusate. 



6. Prom the residue from one of the 

 processes employed, that known as the 

 "ester distillation," I obtained a crystal- 

 line substance having the composition 

 CrHi^NoOj. Dr. Turner and I were finally 

 enabled to identify this substance as 

 a-isobutyl hydantoin (1. isobutyl 2.4 diketo- 

 tetrahydroimidazol) first prepared by 

 Pinner and Lifschiitz^^ and later by Pritz 

 Lippich^^ from valeraldehydeeyanhydrin 

 and urea, also by B. Koenigs and B. Mylo^' 

 from (fZleucinamid and ethylehlorcarbonate. 

 I suspect that other hydantoins are present 

 in the fraction from which this particular 

 hydantoin was isolated. As a-isobutyl 

 hydantoin is the first of its class to be iso- 

 lated from an animal fluid or tissue, one 

 must be certain that the substance has not 

 been formed as a by-product of the many 

 chemical processes that are involved in ob- 

 taining it; in other words, one is obliged to 

 prove conclusively that the substance in 

 question really exists, as such, in the blood 

 of the dog. Por the present we can not 



nBer. d. d. chem. Ges., 20, p. 2,356 (1887). 

 i^Ilid., 41, p. 2,972 (1908). 

 IS Ibid., 41, p. 4,439 (1908). 



offer this final proof. Dr. Turner, how- 

 ever, is now engaged in searching for 

 hydantoins in the blood of the pig by a 

 method that will remove the uncertainty 

 that still attaches to the find as it now 

 stands. 



7. Certain fractions of our dialysates, 

 those derived from the so-called "phospho- 

 tungstic precipitate," have not yet been 

 analyzed in detail, owing to the pressure of 

 other parts of the problem; it is apparent, 

 however, that we are dealing with an inde- 

 terminate number of substances, and it is 

 more than probable that some hitherto un- 

 identified constituents of the blood may 

 here be found. 



Half a year after we made our first com- 

 munication-" in which it was announced 

 that we had separated from our dialysates 

 several grams of amino-acid esters, Abder- 

 halden-^ published a paper in which he de- 

 scribes the separation of some of the amino 

 acids from large quantities of blood ob- 

 tained from slaughter-houses. To secure 

 the small amounts of amino acids needed 

 for his identification tests this investigator 

 was obliged to use at one time 50 or even 

 100 liters of beef blood. These large quan- 

 tities of blood were worked up partly by 

 dialysis, partly by precipitation methods 

 which required the dilution of the blood by 

 many volumes of water. The method of 

 vividiffusion can be used in the most 

 scantily equipped laboratory and has the 

 great advantage of separating the diffusible 

 substances from the proteids of the circu- 

 lating blood of living animals. There can 

 thus be no question here of secondary 



-o"0n the Removal of Diffusible Substances 

 from the Circulating Blood by Means of Dialysis," 

 Trans. Assoc. Americ. Physicians, May, 1913. 

 Also demonstration of our apparatus before the 

 Pharmacological Section, Int. Med. Congress at 

 London, August, 1913. 



ziZeitsohr. f. plujsiol. Chemie, Vol. 88, p. 478, 

 December 23, 1913. 



