250 BLOOD. 



gressive and regressive metamorphosis, we need no longer wonder 

 at these fluctuations. 



Nasse has found more extractive matters in the blood of chil- 

 dren and young animals than in that of the adult species ; the 

 largest quantity was found in human blood, rather less in that of 

 horses, and a much smaller amount in that of oxen. 



From the few analyses which I have made with horses 5 blood, 

 I have been led to the conclusion that more extractive matter is 

 contained in arterial than in venous blood; while the solid consti- 

 tuents of venous serum contained on an average 3'6l7& of extrac- 

 tive matters, those of the arterial serum contained 5*374--. 



The serum of portal blood contains more extractive matters 

 (always determined as free from salts, by the incineration of the 

 ethereal extract freed from fat by water, and of the alcoholic and 

 aqueous extracts) than that of the jugular venous blood; the 

 serum of the blood of the hepatic veins contains, however, the 

 largest quantity of extractive matters. In horses which had 

 been fed (from 5 to 10 hours) previously, I found on an average 

 7'442 of extractive matters (free from salts) in the solid residue of 

 the serum of the portal blood, and a larger quantity, namely, 10{f 

 when the animals had fasted for 24 hours : but from the blood of the 

 hepatic veins I constantly found more than 18g {from 18' 1 to 18'5-g-). 



Amongst the diseases in which the extractive matters are in- 

 creased, we may especially notice puerperal fever (Scherer) and 

 scurvy. 



For the quantitative determination of the salts contained in the 

 serum, it is above all things necessary that we should accurately 

 know the ratio in which the number representing the mineral 

 substances obtained by incineration stands to the number repre- 

 senting the salts which exist pre-formed in the blood, and the 

 manner in which the acids and bases of the ash are grouped in the 

 fresh serum ; we know, however, from what has been previously 

 stated, that we too often find great differences in the constitution 

 of the ash, which depend upon the methods we may have adopted 

 for the carbonisation and incineration of animal substances. Hence 

 it follows that, notwithstanding the careful labour which so many 

 inquirers have devoted to the determination of the saline consti- 

 tuents of the blood, the results in question present little uniformity, 

 or, at ail events, are of such a character as to preclude us from 

 basing any conclusions on them. 



From the best analyses it would seem that the ash of the serum 

 is composed much in the following manner : 



