USES OF THE FATTY PRINCIPLES. 77 



potassa or soda. Some of the fatty principles are, however, not 

 thus decomposed by alkalies, nor by the oxide of lead, and are, 

 therefore, called non-saponifiabk fats. Cholesterine and seroline are 

 of this class. 



It is probable that potassa decomposes fat in the body as well as 

 out of it ; hence the liquor potassse is the most reliable remedy for 

 excessive corpulence. 1 



Uses of the Fatty Principles in the Organism.-^ These have been 

 generally stated on a previous page (p. 75). Certain further par- 

 ticulars should find a place here. 



1. The use of fat in the adipose tissue, or rather of adipose tissue 

 itself, will be specified further on. 



2. The fat in the blood is partly appropriated to the nutrition of 

 the adipose tissue, and partly appears in the form of "oil-drops" in 

 the tissues and in several secretions (p. 75). A portion also enters 

 into organic combination in the structure of the brain ; and, finally, 

 the overplus of the fat is burned up, and thus becomes a calorific 

 material, being converted into carbonic acid gas and water, and thus 

 leaving the body. 



But it is also quite probable that the bile is formed, in part at 4 

 least, from the fat in the blood. Lehmann, however, considers it 

 doubtful if the cholesterine is derived from this source. But the 

 blood of the vena portad contains more fat than that of any other 

 bloodvessel in the body ; besides, it is of a darker brown color, con- 

 tains more oleine, and is therefore more greasy than the fat in other 

 veins. The fact that there is much less fat in the hepatic veins 

 points to the inference that the bile is formed in part from that in 

 the vena portae ; and this is confirmed by the fact; first, that the 

 secretion of bile continues free during starvation, and while ema- 

 ciation is progressing ; secondly, that the blood contains more fat in 

 icterus than in any other disease ; and, thirdly, that a disease of the 

 liver producing diminished secretion of bile also produces obesity, 

 as that occurring in drunkards from nutmeg liver and other diseases 

 of that organ. In acute diseases, also, emaciation first becomes mani- 

 fest in connection with a free discharge of bile from the alimentary 

 canal. (Lehmann.) 



Lehmann expresses the opinion that fat also co-operates in the 

 formation of the blood-pigment, or haBmatine. 



1 See the chapter on "Adipose Tissue." 



