THE LIPOIDS OF MICRO-ORGANISMS 375 



Mycolic acid of Imman and bovine tubercle bacilli 

 m.p. 54-56°, [ajo + 1*8°, C88H176O4, is a saturated acid 

 containing one hydroxyl group, one methoxy group and 

 one carboxyl group. On vacuum distillation at 280° C. it 

 splits to give ?i-hexacosanoic acid, C26H52O2, ni.p. 87-88° 

 and a colorless non-volatile residue. It is the acid-fast 

 staining substance of both organisms. Avian tubercle 

 bacilli give two mycolic acids a- and j3-, both of which are 

 acid fast. On pyrolysis at 210° a-mycolic acid, m.p. 

 69-70°C, [ajc + 5-6°, mol. wi:. 500, gives 25-4 per cent, 

 of a branched chain crystalline pentacosanoic acid, 

 m.p. 78-79°C. and jS-mycolic acid, m.p. 60-61°C., 

 [ajo -f 5-5°, mol. wt. 1300, at 280° C, gives n-tetracosanoic 

 acid, m.p. 83°C. Phleimycolic acid, from the wax of the 

 Timothy grass bacillus, is a mixture of a saturated acid 

 and an unsaturated, dibasic, hydroxy-acid, CToHisgOe, 

 which has m.p. 56-57° and [ajo -f 6-1°. Its methyl ester, 

 on vacuum distillation, gives the volatile methyl ester of 

 a branched chain tetracosanoic acid and a neutral non- 

 volatile residue. The optically active, dibasic, hydroxy- 

 acid, leprosinic acid, from the leprosj^ bacillus has m.p. 

 62-63°, [ajc + 4° and has the formula CgsHi^eOg. 



The specific polysaccharide of the human tubercle 

 bacillus, which occurs in the purified wax and which 

 gives precipitin reactions with homologous antiserum, 

 contains nitrogen and phosphorus and, on acid hydrolysis, 

 yields 2 per cent, of mannose, 36 per cent, of c?-arabinose, 

 17-5 per cent, of galactose and traces of inosito, and 

 glucosamine. The carbohydrate from the bovine o rgan- 

 isms, containing 2-2 per cent, of phosphorus and traces 

 of nitrogen, gives mannose, inositol and inositol mono- 

 phosphate on hydrolysis. 



The acid-fast bacteria contain lipoids which can only 

 be removed by extraction after treatment of the cells 

 with 1 per cent, alcoholic hydrochloric acid. These 



