NON-NITROGENOUS SUBSTANCES IN PLASMA. 159 



Apart from these somewhat doubtful differences in blood from different 

 parts, the amount in the blood remains almost constant, whatever the char- 

 acter of the food, and even during starvation. The amount is somewhat in- 

 creased as the result of haemorrhage, a result due either to accession of lymph 

 (which contains a larger proportion of sugar than does blood), or to the 

 operation, through the agency of the nervous system, causing an increased 

 production of sugar from the liver -glycogen. If the amount of dextrose in 

 the blood be artificially increased to more than aboutO'25per cent, the excess 

 passes off by the urine. The amount is increased in diabetes, whether this be 

 the result of the sugar puncture, of removal of pancreas, or of disease, 1 

 but even under these circumstances does not rise above 048 per cent. 



Fats. These are present in plasma in small but variable quantity 

 (0-2 to 0*5 or even 1 per cent.) 2 being most abundant after a meal 

 containing much fat. The plasma or serum may then be milky from 

 admixture with the fat-containing chyle. They are composed of the 

 usual glycerides of fatty acids (palmitin, stearin, and olein). A small 

 amount, 0'05-O1 per cent., is in the form of soap. 3 It has been stated 4 

 that there is a greater amount of fat (ether extract) in arterial than in 

 venous blood, but this result is shown by Eohmann and Miihsam 5 to 

 have been probably due to an error brought about by venous congestion, 

 which affects the proportion of all the solids of blood as compared with 

 the water. The fatty acids appear also to be partly in combination with 

 cholesterin, forming cholesterin-esters, of which two have been separated 

 by Hlirthle 6 in a crystalline form, namely, the olein and palmitin com- 

 pounds, to the extent in horse serum of 0'08 and 0'06 per cent, respec- 

 tively. Hiirthle further found that in the dog they were increased 

 during inanition. The amount of cholesterin in serum or plasma is 

 stated by Hoppe-Seyler to be about O05 gr. per 100 c.c. blood, 7 and is 

 probably mainly in the form of the fatty acid combinations just referred 

 to, and not, as was formerly supposed, in the free condition (Hiirthle). 



Lipochrome. The yellow-colouring matter of serum is a lipochrome 

 soluble in amylic and also in ethylic alcohol, but insoluble in turpentine. 

 Its absorption spectrum shows two ill-defined bands, 8 one at the F and 

 the other between the F and G Frauenhofer lines (Plate IIL, Fig. 

 24). It resembles the lutein of Kiihne. 



Lactic acid. The presence of sarcolactic acid as a regular con- 

 stituent of normal blood plasma has been affirmed (0'017-0-054 per cent, 

 in dogs). 9 Salomon could only find it in blood from the dead body, not 

 in that drawn during life, 10 but Irisawa confirms its existence in fresh 

 blood (dog), and states that it is present to some extent in the cor- 

 puscles as well as in the plasma. 11 It is increased in blood which has 



1 Pavy, "On Certain Points connected with Diabetes"; Seegen, Wien. med. Wchnschr., 

 1886, S. 1561 and 1595. 



2 Rohrig, Abhandl. d. mouth. -phys. Gl. d. k. Sachs. Gesellsch. d. Wissensch., 1874^ S. 1, 

 and Arb. a. d. physiol. Anst. zu Leipzig. 



3 Hoppe-Seyler, Ztschr. f. physiol. Chem., Strassburg, Bd. viii. S. 503. 



4 Bornstein, Diss.. Breslau, 1887. 



5 Arch. f. d. ges. Physiol., Bonn, 1889, Bd. xlvi. S. 383. 



6 Ztschr. f. physiol. Chem.. Strassburg, 1893, Bd. xxi. S. 331. 



7 Med. Chem. Untersuch./EerliTi, 1866, S. 145. 



8 Kr\\kenbeTg,Sitziingsb.d.Jenaisch. Gesellsch. f.Med.u.Natunv., 1885, Suppl. Bd.xix.S.25. 



9 Gaglio (with Drechsel), Arch. f. Phijsiol., Leipzig, 1886, S. 400; Spiro, Ztschr. f. 

 physiol. Chem., Strassburg, 1887, Bd. i. S. 110 ; Berlinerblau (witli Nencki), Arch. f. 

 exper. Path. u. Pharmakol., Leipzig, 1887, Bd. xxiii. S. 333. 



10 Firchow's Archiv, 1888, Bd. cxiii. S. 356. 



31 Ztschr. f. physiol. Chem., Strassburg, 1893, Bd. xvii. S. 340. 



