153 THE BLOOD. 
in plasma, namely — (1) glycogen ; (2) an animal gnm ; (3) dextrose or 
grape sugar. 
1. Glycogen. — There seems to be no doubt that traces of glycogen can 
be obtained from fresh blood. Some is said to occur free in plasma, but 
if so it is probably derived from intermixed or disintegrated leucocytes, 
which can be shown by histochemical reaction to contain it. 1 Kaufmann 
finds the amount of glycogen in blood to be greatly increased (from O025 
to - 59 per litre) by removal of the pancreas. 2 
2. Animal gum. — Freund 3 has obtained from blood a carbohydrate 
substance, resembling that described by Landwehr under the above name. 
It has the formula (C 6 H 10 O 5 ) n , and is converted by boiling with dilute 
mineral acids into a substance (sugar) which reduces Fehling's solution, 
but is not fermentable, nor is it rotatory for polarised light. Four litres of 
ox blood yielded - 82 grms. of the gum, giving a percentage amount of - 02. 
3. Dextrose. — This is a constant constituent of plasma, whatever the 
nature of the diet, and even in starving animals. 4 It occurs in man to 
the amount of about 012 per cent, of the blood, in the dog from Oil 
to 015 per cent, (or a little over 1 per 1000). 5 It is present in 
nearly ecpial amount in blood from all parts, except in the blood of the 
portal vein, during digestion of carbohydrate-containing foods, where 
it is markedly increased. In the blood of the hepatic veins, in the 
intervals of digestion, the amount was stated by Bernard to be some- 
what greater than in the portal vein, or in the blood of the general cir- 
culation ; but this difference has not been found by Pavy and most other 
observers, although the statement has of late been reaffirmed by Seegen. 6 
Bernard 7 obtained a larger amount of sugar from arterial than from 
venous blood, and Seegen has in some instances obtained a similar 
result. Chauveau, 8 and Chauveau and Kaufmann, 9 have also published 
analyses, which seem to show a disappearance of sugar after passing 
the capillaries. But the differences observed have not been constant, 
and are in any case so small as to lie within the range of experimental 
error. As the result of eleven experiments, Pavy finds the sugar in 
arterial blood to exceed that in venous by only - 003 parts per 1000 ; 
and he concludes that no appreciable difference exists between the two. 10 
1 E. A. Schafer, "A Course of Practical Histology," London, 1876, p. 39; Salomon, 
Deutsche Tried. JVchnschr., Leipzig, 1877, S. 92 and 421 ; Arch. f. Physiol., Leipzig, 1878 ; 
Centralbl. f. Physio/., Leipzig u. Wien, 1892, Bd. vi. S. 512; Ehrlich, Ztschr.f. Mill. Med., 
Berlin, 1S83, Bd. vi. S. 40 ; Gabritschewsky, Arch. f. exper. Path. u. Pharmakol., Leipzig, 
1891, Bd. xxviii. S. 272; Huppert, Centralbl. f. Physiol., Leipzig u. Wien, 1892, No. 
14, S. 394 (Huppert found more in dog's blood than in the blood of herbivora) ; Hoppe- 
Seyler, Ztschr.f. physiol. Chem., Strassburg, 1894, Bd. xviii. S. 144. 
2 Compt. rend. Acad. d. sc, Paris, 1895, tome cxx. p. 567. 
3 Centralbl. f. Physiol., Leipzig u. Wien, 1892, Bd. vi. S. 345. 
4 CI. Bernard, Arch. gin. de mid., Paris, 1848, tome xviii. p. 303; Pavy, Phil. Trans., 
London, 1860 ; v. Mering, Arch. f. Physiol., Leipzig, 1877, S. 379 ; Otto, Arch. f. d. ges. 
Phi/siol.. Bonn, 1885, Bd. xxxv. S. 467; Piekardt, Ztschr. f. physiol. C'hcm.. Strassburg, 
Bd. xvii'. S. 217; Miura, Ztschr.f. Biol., Miinchen, Bd. xxxii. S. 255. 
5 Pavy, " Physiology of the Carbohydrates," 1894, p. 161. 
6 Arch. f. cl. ges. Physiol., Bonn, 1884, Bd. xxxiv. S. 3S8, and 1885, Bd. xxxvii. S. 
348; Centralbl. f. Physiol., Leipzig u. Wien, 1893, No. 12; " Zuckerbildung im Thier- 
korper," 1S90. 
7 Compt. rend. Acad. d. sc, Paris, tome lxxxiii. p. 373, and " Lecons sur le Diabete," 1877. 
8 Ibid., 1856, tome xliii. p. 1008. 
9 Ibid., 1886, tome ciii. p. 974. 
10 Pavy, Proc. Roy. Soc. London, 1877, vol. xxvi. p. 346 ; "On Certain Points connected 
with Diabetes," London, 1878; " Physiology of the Carbohydrates," pp. 170-171. This 
is also apparently admitted by Seegen ("La Glycogenic Animale," Paris, 1890, p. 100), 
although his theory of the production of energy requires that there should be a diminution 
in the amount of su«ar in venous blood. 
