80 BACTERIAL POISONS OF INFECTIOUS DISEASES. 



beeswax. The total amount of fatty substances contained in the 

 tubercle bacillus varies from 8 to 26 per cent. 



According to Euppel, the soluble albuminous substances contained 

 in the tubercle bacillus are best obtained by the action of superheated 

 steam on bacilli previously deprived of their fatty content. The 

 procedure recommended is as follows : The bacilli are first extracted 

 with a 1 per cent, soda solution or heated with a dilute solution of 

 glycerin, thoroughly extracted with alcohol and ether, dried and 

 rubbed into a fine powder, which is then treated with ten times its 

 volume of 5 per cent, glycerin solution and kept in the autoclave at 

 150° for about two hours. The extract thus obtained is filtered 

 while still hot, and it is found that the filtrate, at first clear, forms a 

 deposit on standing, and complete separation may be obtained in the 

 centrifuge. The soluble proteids obtained in this way constituted 

 from 18 to 20 per cent, of the total weight of the bacilli, and con- 

 sisted exclusively of albumoses analogous to the atmidalbumose of 

 Neumeister. The solution of mixed atmidalbumoses is dark in 

 color and may be precipitated by ammonium sulphate, sodium 

 chlorid, or, best of all, with absolute alcohol after the addition of a 

 small amount of sodium chlorid and hydrochloric acid. On drying, 

 the alcoholic precipitate is found to consist of a light powder, which, 

 as has been stated, constitutes about 20 per cent, of the fat-free 

 bacilli. 



Ruppel finds that when tubercle bacilli have been finely broken 

 up, they give up about half their substance to aqueous extracts. 

 When finely divided tubercle bacilli are shaken in water there is 

 formed a milky emulsion, and this, when placed in the centrifuge, 

 separates into a transparent, feebly opalescent, yellowish fluid, and a 

 deposit. When this deposit is dried and weighed it is found to con- 

 stitute about half the weight of the powdered bacilli originally taken. 

 The reaction of the fluid portion is generally feebly alkaline, but 

 may be neutral. It contains no coagulable proteid, and of the 

 general color reactions, it responds only to the biuret test. Acetic 

 acid produces a considerable precipitate, which is not soluble in 

 excess, but which dissolves in dilute alkalis, from which it may be 

 precipitated anew on the addition of acids. The acetic acid precipi- 

 tate contains a little more than 4 per cent, of phosphorus. It 

 responds to neither the Millon nor the xanthoproteic test, but the 

 biuret reaction is positive. When dissolved in glacial acetic acid 

 and warmed with sulphuric acid, it does not give a red coloration. 

 About 25 grams of this substance was shaken with 1 per cent, sul- 

 phuric acid, and the acid extract thus obtained was precipitated by 

 the addition of absolute alcohol. The precipitate was found to con- 

 sist of a snow-white, flocculent powder, and the amount obtained 

 was 0.7 of a gram. It is soluble in warm water, from which it 

 partially deposits on cooling. When dissolved in warm water, the 



