TUBERCULOSIS. 79 



that this body corresponds closely to teraconic acid and its discoverer 

 believes that the necrotic effects observed in tuberculosis are due to 

 this agent. It is also a fever-reducing substance, while the albu- 

 minoid obtained from cultures of the tubercle bacillus causes an ele- 

 vation of temperature. 



Klebs ' states, as a result of his investigations, that the tubercle 

 bacillus contains two fatty bodies. One of these may be extracted 

 with ether ; it has a reddish color, melts at 42°, and constitutes 20.5 

 per cent, of the weight of the bacillus. The other fat is insoluble in 

 ether, but may be extracted with benzol ; its melting point has not 

 been accurately determined, but is something over 60°, and it con- 

 stitutes 1.14 per cent, of the substance of the germ. The specific 

 coloration of tubercle bacillus with carbolic fuchsin is due to the 

 presence of these fatty bodies, and after their removal the bacilli, 

 although retaining their form, fail to stain. - The greater part of the 

 tubercle bacillus, after the removal of the above-mentioned fats, con- 

 sists of a nuclein, which may be purified after digestion with pepsin 

 and hydrochloric acid, by solution in dilute alkalis and precipitation 

 with alcohol. In this way Klebs obtained a nuclein which yielded 

 between 8 and 9 per cent, of phosphorus. The third important con- 

 stituent of the tubercle bacillus is the glycerin-water extract, which 

 probably consists of a mixture of substances, some of which are pro- 

 teid in character. 



Euppel * thinks that there are three kinds of fatty substances in 

 the tubercle bacillus. The first constitutes about 8 per cent, of the 

 total weight of the organism, from which it can be removed with cold 

 alcohol. During the process of extraction the alcohol becomes in- 

 tensely red, and this is supposed to be due to a chromogen 

 ■contained in the bacillus, which develops into the coloring matter on 

 ■exposure to air. On evaporation of this alcoholic extract there re- 

 mains a smeary mass, consisting largely of free fatty acid. When 

 the free fatty acids are removed by the ordinary method of treatment 

 with soda solution and ether, the mass obtained on the evaporation 

 of the ether melts between 55 and 60°. This substance is easily 

 saponified, and contains along with the free fatty acids another sub- 

 stance soluble in ether, which is believed to be one of the higher 

 alcohols. The second form of fat contained in the bacillus may be 

 extracted from the residue left after extraction with cold alcohol, by 

 means of hot alcohol. This substance begins to liquefy at 65°, but 

 does not become altogether clear until a temperature of 200° is 

 reached. The hot alcoholic extract saponifies with difficulty, and 

 appears to consist of fatty esters of the higher alcohols. The third 

 fatty substance may be removed by means of ether. It melts at from 

 65 to 70°, and on being heated gives off an odor similar to that of 



1 CentralbkUtf. BaUo'iohgie,' 20, 488. 

 'ZeUschriftf. physiol. Chemie, 26, 1899. 



