526 SCIENCE PROGRESS 



The next part of the work was devoted to the determination 

 of the seat of ammonia formation. In conjunction with 

 Zaleski, a method was devised for the determination of minute 

 quantities of ammonia in the blood and tissues, and by means 

 of this method a series of estimations of ammonia in organs 

 and blood from different parts of the body was made. It 

 was found that the blood in the portal and mesenteric veins 

 contained larger amounts of ammonia than other parts of the 

 vascular system. Furthermore, large amounts of ammonia were 

 obtained from the mucous membrane of the digestive tract. 

 Finally, the tissues of well-fed animals yield more ammonia 

 than those of fasting animals. These results leave little 

 doubt that it is in the tissues of the alimentary tract that the 

 elimination of ammonia from the products of protein digestion 

 takes place. Passing from this locality to the liver in the form 

 of ammonium carbonate or carbamate, they are then converted 

 from the toxic form into the non-toxic urea, which is then 

 rapidly eliminated in the urine. 



It was shown that after Eck's fistula atrophy of the liver 

 takes place. We now know that unless this organ is supplied 

 with excess of alkali, the autolytic enzyme comes into play 

 and brings about hydrolysis. We do not yet know why, 

 however, the animal only survives the total extirpation of this 

 organ but a very few hours, as was demonstrated by Nencki 

 and Pawlow in the case of dogs, and by Minkowski in the case 

 of geese. 



The results on urea formation are of considerable interest 

 from the clinical standpoint. They indicate the importance of 

 full urine analyses for the purpose of diagnosis, especially in 

 diseases of the liver. Much remains to be done in this direction, 

 but it is hoped that the simplification of urine analysis by the 

 methods of Morner, Folin, and others may stimulate further 

 work in this direction. 



IV. Researches on the Animal Pigments. 



These investigations were carried out principally in conjunc- 

 tion with Zaleski and Madame Sieber. More than fifty years 

 ago, Teichmann had observed that when a drop of blood is 

 mixed with glacial acetic acid and allowed to evaporate at a 

 gentle heat over a small flame, crystals separate, which have 

 since that time been known as Teichmann's crystals. Nencki 



