ACTION OF POTASH UPON CHOLESTERINE. 



For some reasons we would be induced to place cholesterine 

 among the fatty bodies, but from many of its characters it 

 would appear certainly not to belong to this class of bodies. 

 The most important distinctions between these two bodies 

 are, first, the want of- action of a solution of potash upon 

 cholesterine; and secondly, its high point of fusion, which is 

 298° Fah.* 



Another difference which I am able to point out is that cho- 

 lesterine is heavier than water, whereas the fats are lighter. 

 It will be found in works on chemistry that cholesterine is 

 lighter than water, and I attribute this to the fact that the 

 substance, as it crystallizes out of alcohol, was found to float 

 on the surface of water; but this is owing to the air adhering 

 to the crystals. To show that it is heavier all that is necessary 

 to be done is to throw a small piece of fused cholesterine into 

 a vessel containing water, that must afterward be made to 

 boil (this is done to drive away the air adhering to the surface 

 of the body) ; after which it will be found to sink, and remain 

 at the bottom of the vessel even when the water is cold. I 

 dwell thus much upon this because I feel confident that there 

 are other organic bodies that are said to be lighter than water, 

 but which are actually heavier; for, owing to the looseness of 

 their structure, air insinuates itself between the molecules, and 

 is afterward held so firmly that it is impossible to drive it 

 away by the ordinary means. I now return to the first dis- 

 tinguishing character between cholesterine and the fats — the 

 difference of the action of potash upon the two bodies. 



Chevreul and others have shown that if cholesterine be 

 digested a great length of time in a boiling solution of potash 

 no change takes place; but here the cholesterine is not sub- 

 jected to the action of the potash under the same circumstances 



* The melting-point of most of the fats is below 140°. 



