334 THE BLOOD. 



urea in normal blood. The quantity of urea is somewhat increased in 

 fever, and in general in augmented protein metabolism the increased 

 urea formation is dependent upon this. A more important increase in the 

 quantity of urea in the blood occurs in a retarded elimination of urea, 

 as in cholera, also in cholera infantum, and in infections of the kidneys 

 and urinary passages. After ligaturing the ureters or after extirpation 

 of the kidneys of animals, an accumulation of urea takes place in the 

 blood. 



v. SCHRODER first showed that the blood of the shark was very rich 

 in urea, and the quantity indeed amounted to 26 p. m. BAGLIONI 1 

 has recently shown that this large quantity of urea is of the greatest 

 importance, as the presence of urea in these animals is a necessary life- 

 condition for the heart and very probably for all organs and tissues. 



The blood also contains traces of ammonia. According to HORODYN- 

 SKI, SALASKIN, and ZALESKi, 2 the quantity in arterial dog-blood was 

 0.41 milligram in 100 grams of blood. According to WINTERBERG, S the 

 blood from healthy persons contains on an average 0.90 milligram per 

 100 cc. 3 The .quantity of uric acid may be 0.1 p. m. in bird's 

 blood (v. SCHRODER 4 ). Uric acid has only recently been positively 

 detected under normal conditions, while it has been found, earlier, 

 in the blood in gout, croupous pneumonia, and certain other diseased 

 conditions. FOLIN and DENIS 5 have determined the uric acid in the 

 blood of certain animals as well as in man by a colorimetric method 

 suggested by FOLIN. Normal human blood contains not less than 1 

 to 2-2.5 milligrams uric acid per 100 grm.; in gout they found 5.5 

 milligrams as maximum. They also determined the quantity of total 

 non-protein nitrogen and urea nitrogen in human blood. In normal 

 blood the first was equal to 22-26 milligrams and the last equal to 11-13 

 ( = 24-28 urea) milligrams in 100 grams of blood.. In disease great varia- 

 tions were found. Lactic acid was first found in human blood by 

 SOLOMON and then by GAGLIO, BERLINERBLAU, and IRISAWA. The 

 quantity of lactic acid may vary considerably. BERLINERBLAU found 

 0.71 p. m. as maximum, in dog's blood. SAITO and KATSUYAMA 6 found 

 on an average 0.269 p. m. in hen's blood, and after carbon-monoxide 

 poisoning the quantity increased to 1.227 p. m. Fat and fatty acids occur 



1 v. Schroder, Zeitschr. f. physiol. Chem., 14; Baglioni, Centralbl. f. Physiol., 19. 



2 Zeitschr. f. physiol. Chem., 35, which also gives the older literature. t 



3 Wien. klin. Wochenschr., 1897, and Zeitschr. f. klin. Med., 35. 



4 Ludwig's Festschrift, 1887. 



6 Journ. of biol. Chem., 13 and 14. 



6 Irisawa, Zeitschr. f. physiol. Chem., 17, which also gives the older literature; 

 Saito and Katsuyama, ibid., 32. 



