372 BACTERIOLOGICAL CHEMISTRY 



of high molecular weight ; cholesterol has the structure :- 



CH, 



CH, 



-CH, 



.CH.{CH2)3CH 



CH, 



CH, 



CH3 CH3 CHg 



1 I / 



CH.CH^CH.CH.CH 



"^CH, 



/ 



CH, 



\/ 

 and ergosterol, 



CH, 



HO 



In view of their exceptionally high lipoid content 

 the acid-fast bacteria have naturally been most closely 

 examined in this respect. As early as 1898 a wax re- 

 sembling beeswax had been isolated from the tubercle 

 bacillus, and in 1904 a higher alcohol was isolated. In 

 1914 Tamura isolated an alcohol, C29H55OH, m.p. 66° C, 

 which he named mykol. He showed that it stained 

 Gram positive and had the property of acid-fastness ; he 

 ascribed these properties of the tubercle bacillus to mykol. 

 Other alcohols, including phytoglycol, C26H54O2, have 

 also been isolated from the tubercle bacillus, together with 

 a wax shown to be an ester of mykol with lauric acid. 

 R.J. Anderson and his co-workers have shown that most 

 of the " waxes " of the acid-fast bacteria consist of 



