THE SPLIT PRODUCTS OF TUBERCLE BACILLUS 165 



the powder shows the bacilli more or less broken into a 

 cellular debris when examined microscopically. The indi- 

 vidual bacilli take the carbolic stain, but this is now 

 washed out with dilute nitric acid. 



The Cleavage of the Cell. The cellular substance, pre- 

 pared as stated above, is placed in large flasks, fitted with 

 reflux condensers, covered with from fifteen to twenty 

 times its weight of absolute alcohol, in which 2 per cent, 

 of sodium hydroxide has been dissolved, and heated for 

 one hour at 78, the boiling-point of absolute alcohol. 

 Three successive extractions are made, using a new portion 

 of alkaline alcohol each time. This treatment splits the 

 cellular substance into two portions one soluble and the 

 other insoluble in absolute alcohol. These portions we will 

 designate as the "cell poison" and the "cell residue." 



The Cell Poison. This is soluble in the alcohol, which is 

 carefully neutralized with hydrochloric acid. The precipi- 

 tated sodium chloride is removed by filtration and the 

 filtrate containing the poison is evaporated in vacua at or 

 below 40. This leaves the cell poison as a brownish mass 

 containing a small amount of sodium chloride, which can 

 be removed by repeated solutions in absolute alcohol and 

 evaporation. The poison resembles that obtained from other 

 protein bodies. It is freely soluble in absolute alcohol ; less 

 freely in water. Its aqueous solutions give all the color pro- 

 tein reactions, including that of Molisch, which is not given 

 by the poisonous groups that we have obtained from other 

 proteins. In powder form it is deliquescent and becomes 

 darker as it absorbs water. The tubercle protein apparently 

 contains much less poison than the cellular proteins of the 

 colon and typhoid bacilli. The latter are split up by our 

 method into about one-third poison and two-thirds residue, 

 while 25 grams of the cellular substance of the tubercle 

 bacillus yielded less than 3 grams of poison. 



The Cell Residue. This is the portion insoluble in the 

 alkaline alcohol. It is placed in Soxhlets and extracted for 

 many hours with absolute alcohol in order to remove 

 traces of the cell poison and free alkali. After this it is 



