v THE BLOOD: PLASMA 127 



continued by many experiments carried out by Fauo and his pupils 

 Ducceschi and di Frassineto, who studied the blood in anaemia, iu 

 the two sexes, after thyroidectomy, etc. 



The serum of mammalian blood contains a saccharifying 

 ferment, as was pointed out by Magendie, Cl. Bernard and others. 

 Bial found that the blood of man (obtained by bleeding, or taken 

 from the placenta) also contained the power, although in a lesser 

 degree, of converting starch paste into glucose and dextrin, and is 

 further capable of converting maltose into dextrose. In the new- 

 born, in man as in other animals, the saccharifying property is 

 very low, and may be entirely absent ; it increases with age, and 

 with its increase there is an apparent diminution in the glycogeu- 

 content of the muscles. 



E. Cavazzani found that the quantity of haemo-diastase is not 

 alike throughout the vascular system ; the blood of the portal 

 veins contains more than the blood of the hepatic veins, the 

 jugulars, and the carotid arteries. This leads to the conjecture 

 that it originates in the digestive organs, and that its presence in 

 the blood is to a certain extent fortuitous, and dependent on 

 digestive processes. 



According to recent researches, blood serum contains various 

 other enzymes. 



Claude Bernard (in his observations on the amount of glycogen 

 in normal dog's blood) found it necessary to test for glycogen 

 immediately after the blood had been drawn from the vessels of the 

 animal, because in a longer or shorter period, according to the sur- 

 rounding temperature, it was destroyed by a fermentative process. 



A similar disappearance of glycogen (as also of laevulose, 

 maltose, and galactose) occurs on adding sugar artificially to the 

 blood in vitro, and it was more particularly after the researches of. 

 Lepine and Barral that this disappearance of sugar in the blood 

 was attributed to the action of a special glycolytic enzyme, which, 

 according to these authors, originated in the white corpuscles. 

 This glycolysis is effected, according to Nasse, Eohmann and 

 others, by an oxidative process, and more precisely by the agency 

 of an oxidising ferment (oxidase), while according to Stoklasa it is 

 due to a process analogous to alcoholic fermentation, to the agency, 

 that is, of a special zymase. 



In addition to these two amylo- and glycolytic enzymes there 

 exists in the serum, according to Hanriot, a lipolytic ferment 

 (lipase), which, according to most authors, acts only on mono- 

 butyrin, and is incapable of splitting up olein and other neutral 

 fats (Arthus, Doyen and others). 



Along with this restricted lipolytic property of serum, the 

 blood, according to Connstein and Michaelis and Weigert, has also 

 a property of transforming fats into certain soluble substances, the 

 composition of which is not known. 



