MINUTE STRUCTURE OF THE BACTERIAL CELL 63 



(butter bacillus), and others. In other species no fat was de- 

 monstrated by Sudan III. -Bacteria form the most of their 

 fat when grown on potato or glycerine agar. The amount 

 of the fat in a bacterial cell may be increased by growing the 

 bacteria on a fat-rich medium. 



Kresling l gives the following analysis of the material after 

 extracting Bacterium tuberculosis with chloroform. 



Free fatty, acids 14.38 per cent 



Neutral fats and fatty acid esters 77.25 per cent 



Alcohols obtained from fatty acid esters 39. 10 per cent 



Lecithin 0.16 per cent 



Substances soluble in water 0.73 per cent 



The foregoing analysis shows the fatty derivatives which 

 may be present in one species of bacteria. 



It has been noted by some chemists that the etherial 

 extracts do not contain the acid-fast substances. It has 

 been claimed that the so-called acid-fast substance is an 

 alcohol having some of the properties of a wax. This sub- 

 tance was soluble in hot absolute alcohol or ether and insoluble 

 in cold alcohol and ether, thus suggesting its similarity to a 

 *wax. Olei'c, isocetinic, and nysistinic, and some saponified 

 lauric acids are present, and it is from them that the fats are 

 formed. 



In all probability the insoluble cell wall of bacteria is 

 not composed of pure cellulose. The idea that the wall or 

 limiting membrane of the cell was composed of cellulose 



1 Quoted from Wells' " Chemical Pathology." 



