BACILLI IN CHRONIC INFECTIOUS DISEASES. 387 



importance in scientific medicine, whatever the final verdict may be 

 as to its therapeutic value in tubercular diseases in man. 



The toxic substance contained in Koch's glycerin extract from 

 cultures of the tubercle bacillus, now generally known under the 

 name of tuberculin, is soluble in water, insoluble in alcohol, and 

 passes readily through dialyzing membranes. It is not destroyed by 

 the boiling temperature. According to the chemical examination of 

 Jolles, the " lymph " contains fifty per cent of water and does not 

 contain alkaloids or cyanogen compounds. Ib contains albuminates, 

 which are thrown down as a voluminous white precipitate by tannic 

 acid, and are redissolved by hot water containing sodium chloride 

 and very diluted potash solution. The elementary analysis gave 

 N" 5.90 per cent, C 35.19 per cent, and H 7.02 per cent. The re- 

 sults obtained are believed to show that the active substance present 

 in the lymph is a toxalbumin. In experiments made with Koch's 

 lymph in Pasteur's laboratory by Bardach, a very decided elevation 

 of temperature was produced in tuberculous guinea-pigs by the sub- 

 cutaneous injection of 0.1 gramme, and a fatal result by the injec- 

 tion of 0.2 to 0.5 gramme. In man a decided febrile reaction is pro- 

 duced in tuberculous patients by very much smaller doses 0.001 

 cubic centimetre. 



Hammerschlag, in his chemical researches, found that the tubercle 

 bacillus yields a larger proportion of substances soluble in alcohol 

 and ether than any other bacilli tested (twenty -seven per cent). The 

 alcoholic extract contains fat, lecithin, and a toxic substance which 

 produces convulsions in rabbits and guinea-pigs. The portion in- 

 soluble in alcohol and ether contains cellulose and an albuminoid 

 substance. No ptomaines were found, but a toxalbumin was isolated, 

 which caused an elevation of temperature in rabbits of 1 to 2 C., 

 lasting for a day or two. 



Hunter reports the following results of his chemical examination 

 of tuberculin. It contains 



1. Albumoses, chiefly protoalbumose and deuteroalbumose, along with 

 heteroalbumose, and occasionally a trace of dysalbumose. 



2. Alkaloidal substances, two of which can be obtained in the form of 

 the platinum compounds of their hydrochlorate salts. 



3. Extractives, small in quantity and of unrecognized nature. 



4. Mucin. 



5. Inorganic salts. 



6. Glycerin and coloring matter. 



The following conclusions are reached with reference to its toxic 

 properties- : 



1. Tuberculin owes its activity, not to one principle, but to at least three, 

 and probably more, different substances. 



2. Its action in producing local inflammation, fever, and general consti- 

 tutional disturbance is not a simple but an extremely complex one. 



