

BIOLOGICAL PROPERTIES 323 







and Widal) and after exposure to running water for 150 days (Cadeac and 

 Malet). 



Putrefaction has little effect on the tubercle bacillus. Tuberculous tissues 

 left to decompose in water for 20 and 40 days did not lose their virulence 

 (Gal tier). Tuberculous lungs buried for 167 days have been found to be 

 virulent (Cadeac and Malet). Schottelius found that the bacillus was virulent 

 in tissues which had been buried for 2 years. Gsertner made the same observa- 

 tion after burying the tuberculous tissues for a winter. 



Action of antiseptics. In cultures, the tubercle bacillus is somewhat 

 sensitive to the action of antiseptics. According to Yersin it is killed in 

 30 seconds in a 5 per cent, solution of phenol ; in 5 minutes in absolute 

 alcohol, and in 1 per cent, iodoformed ether ; in 10 minutes in a 1 in 1000 

 solution of perchloride of mercury, and after several hours in 0'3 per cent, 

 thymol or 0'25 per cent, salicylic acid. It resists the action of 4 per cent, 

 boric acid for more than 12 hours. 



According to Koch, the following substances readily hinder the growth of 

 the bacillus in cultures, viz. : the essential oils, naphthol, fuchsin, methy- 

 lene blue, gentian-violet, and especially the cyanides of gold and silver. 

 Cyanide of gold in the proportion of 1 part in 2 millions stops the growth of 

 the bacillus. 



But in tuberculous fluids and tissues the resistance of the bacillus is much 

 greater : thus 1 in 500 salicylic acid, 1 in 1000 bromine, creosote, quinine, 

 1 in 1000 perchloride of mercury, and formalin vapour have no effect on the 

 bacillus. Six per cent, carbolic acid has a doubtful influence, a 1 in 4000 

 solution of hydrofluoric acid (a very caustic liquid) has hardly any action 

 (H. Martin). The numerous experiments of Vallin, Mairet, Cavalier, Coze 

 and Siamon and others have given contradictory results. 



2. Toxins. 

 A. Toxic properties of dead tubercle bacilli. 



Koch and many other observers have found that agar cultures sterilized 

 by heat at 100 C. are injurious to animals, and that in sufficiently large 

 doses they lead to suppuration, cachexia and death in guinea-pigs. Dead 

 tubercle bacilli inoculated into the blood or peritoneal cavity [of the guinea- 

 pig] lead to the formation of true tubercles in which the presence of the 

 dead bacilli can be demonstrated, but these lesions do not become generalized 

 nor are they capable of being passed on to another animal. When only 

 a small dose of dead bacilli is inoculated the lesions disappear spontaneously 

 after a few months and the animal recovers (Cautacuzene). The more 

 virulent the living bacilli the more toxic the dead bacilli. 



[F. Griffith (English Commission) observing that the intra- venous inocu- 

 lation of living mammalian tubercle bacilli in doses of 10-50 mg. caused 

 death in about 50 per cent, of fowls, inoculated 3 fowls each with 10 mg. of 

 bovine tubercle bacilli killed by exposure to steam at 100 C. and found in 

 the lungs of two of them after 38 days numerous minute caseating tubercles. 

 He concluded that the fatal infections were due to the direct toxic action of 

 the bacilli and were not true tuberculosis. 



[Similar results were obtained in fowls inoculated with dead human and 

 avian tubercle bacilli ; the latter were not more toxic for the fowl than the 

 mammalian types.] 



Hammerschlag treated dried tubercle bacilli with alcohol and ether. He 

 obtained a product which was toxic to guinea-pigs and rabbits. The inocu- 

 lated animals had convulsions and died. 



