128 THE BLOOD AND ITS CIRCULATION. 



indeed, we find, in addition to the albumen, a series of 

 albuminoid substances called peptones, not coagulable by 

 heat, and appearing particularly well adapted for transforma- 

 tion easily and readily into the form of tissue. It is more 

 likely that the principal use of ordinary albumen is to pre- 

 vent the adhesion of the blood to the coats of the vessels. 



The serum contains various fatty matters. In some cases 

 it is difficult to account for the presence of these fats. Thus, 

 in the case of persons who are habitual inebriates, drops of 

 fat are sometimes found floating in the blood; after an abun- 

 dant meal, also, an accumulation of fatty globules is found in 

 the blood, which, however, soon disappear. A fatty sub- 

 stance, also, which is not capable of saponification, is gen- 

 erally found in the serum (cholesterine) ; this is admitted to 

 be an excrementitious product (to be rejected by the liver). 

 In addition to these fats are found the fatty elements (mar- 

 garine, oleine; margarates and oleates of soda) and fat acids 

 peculiar to each animal, and which may be removed by means 

 of sulphuric acid. These volatile fat acids, when thus re- 

 jnoved, emit a peculiar odor, by means of which the blood 

 of man can be distinguished from that of other animals, and 

 it has even been asserted, the blood of a man from that of a 

 woman. The sum total of fatty matters contained on an 

 average in the blood is from 2 or 3 grammes in a litre. 



There are, besides,, found in the liquor some compositions 

 which it is difficult to classify, known by the name of extrac- 

 tive matters. Among these complex substances we will men- 

 tion the lactic acid and the lactates, which are formed, no 

 doubt, principally during the process of digestion ; also, the 

 pneumic acid, whose existence is still doubtful, but which is 

 probably due to a reaction in the lung, which releases the 

 carbonic acid from the venous blood ; also, the urea and uric 

 acid, excrementitious products destined to be thrown off, 

 whose retention in the blood is highly dangerous ; also, the 

 creatine and creatinine. 



We must also mention here the coloring matters which, 

 no doubt, originate in the globules, reappearing in some 

 secretions, especially in the bile ; and, finally, those composi- 

 tions, belonging to the class of sugars, which arise partly 

 from the ingested substances, and partly also, perhaps, from 

 the transformations which take place in the different tissues, 

 glands, and particularly in the liver ; their function is, per- 

 haps, more essentially glycogenic (see " digestion ; functions 

 of the liver"). 



