Toxic Products 737 



cold alcohol, the second with hot alcohol, the third with 

 ether. In addition to the fatty substance Ruppel also 

 found what he believes to be a protamin, and calls tuber - 

 culosamin. It seems to be combined with nucleinic acid, 

 and, indeed, from it he isolated an acid for which he proposes 

 the name tuber culinic acid. 



Behring* found that this acid contained a histon-like 

 body whose removal left chemically pure tuber culinic acid. 

 One gram of this acid is capable of killing a 6oo-gram guinea- 

 pig when administered beneath the skin. One gram is 

 fatal to 90,000 grams of guinea-pig when introduced into 

 the brain. If injected into tuberculous guinea-pigs it is 

 much more fatal, i gram destroying 60,000 when injected 

 subcutaneously and 40,000,000 when injected into the 

 brain. 



Levenef also found free and combined nucleinic acid 

 varying in phosphorus content from 6.58 to 13.19 per cent. 

 He also found a glycogen-like substance that reduced 

 Fehling's solution when heated with a mineral acid. 



Toxic Products. In 1890 Koch I announced some ob- 

 servations upon the toxic products of the tubercle bacillus 

 and their relation to the diagnosis and treatment of tubercu- 

 losis, which at once aroused an enormous though transitory 

 enthusiasm. The observations are, however, of great 

 importance. Koch found that when guinea-pigs are 

 inoculated with tubercle bacilli, the wound ordinarily heals 

 readily, and soon all signs of local disturbance other than 

 enlargement of the lymphatic glands of the neighborhood 

 disappear. In about two weeks, however, there appears, 

 at the point of inoculation a slight induration, which develops 

 into a hard, nodule, ulcerates, and remains until the death 

 of the animal. If, however, in a short time the animals be 

 reinoculated, the course of the local lesion is changed, and, 

 instead of healing, the wound and the tissue surrounding it 

 assume a dark color, become obviously necrotic, and ulti- 

 mately slough away, leaving an ulcer which rapidly and 

 permanently heals without enlargement of the lymph- 

 glands. 



This observation was made by injecting cultures of the 

 living bacillus, but Koch observed that the same changes 



*" Berliner klin. Wochenschrift," xxxvi. 

 t " Jour, of Med. Research," I, 1901. 

 J "Deutsche med. Wochenschrift," 1891, No. 343. 

 47 



