ORGANIC CONSTITUENTS 59 



members of the acid-fast group. In some members of this group 

 the extractives vary from 20 to 40 per cent, of the total dry residue. 

 In the early studies of the chemistry of bacterial cells it was assumed 

 that the alcoholic and ethereal extracts consisted of fats exclusively. 

 Tributyrin, tripalmatin, tristearin, triolein, lecithin and various 

 waxes have been recognized. 



Klebs found in the tubercle bacillus 20.5 per cent, of a red fat 

 melting at 42 and 1.14 per cent, of a white fat melting above 50, 

 the latter being insoluble in ether but soluble in benzol. De Schwei- 

 nitz and Dorset concluded that the fat of the tubercle bacillus con- 

 tains palmitic and arachidic acids, while that of the glanders bacillus 

 contains oleic and palmitic. They also obtained a crystalline acid, 

 for which they suggested the name tuberculinic acid. This is quite 

 different from Ruppel's nucleic acid. It had an elementary com- 

 position of C 7 Hi O4. The authors called attention to the similarity 

 in composition and properties of this body and tetraconic acid. 

 They suggest that it may be the substance which is responsible 

 for the coagulating necrosis and reduction in temperature. 



Kresslig extracted tubercle bacilli successfully with ether, chloro- 

 form, benzol and alcohol, and obtained 38.95 per cent, of fatty and 

 waxy substances. Repeated extraction with chloroform gave a 

 dark brown mass of the consistency and color of beeswax and melting 

 at 46. He found 14.38 per cent, of free fatty acid, 77.25 per cent, 

 of neutral fat and esters of fatty acids, and some volatile fatty 

 acid, probably butyric. He concluded that the fat of the tubercle 

 bacillus is quite different from that obtained from any other source. 



The fats and waxes are probably both intra- and extracellular, 

 for extraction of the intact cell yields some and the crushed cell 

 yields still more. The quantity found within the cell varies greatly, 

 depending on the media upon which the organism is grown. Meyer 

 found that the fat in Bacillus tumescens gradually increases until 

 spore formation occurs, when it disappears; the spores are also free 

 from fat. This, however, is not general for the spores of some 

 organisms contain proportionally more fat than do the vegetative 

 forms. 



Proteins. The bulk of the dry matter of the bacterial cell is com- 

 posed of proteins. The following analysis reported by Iluppel 

 indicates the composition of the tubercle cell: 



Nucleic (tuberculinic acid) ........ 8.5 per cent. 



Nucleoprotamin 25.5 



Nucleoproteid 23.0 



Albuminoids * . 8.3 



Fat and wax 26.5 



Ash . . 9.2 



The wonderful synthetic reaction catalyzed by the Azotobacter cell 

 has directed the attention of workers to this specific organism. 



