294 TUBERCULOSIS 



the bacilli are dead they preserve their staining reactions in 

 the tissues for a long time, and also that there are apparently 

 contained in the bodies of the dead bacilli certain substances 

 which act locally, producing proliferative and, to a less extent, 

 degenerative changes, and which also markedly affect the general 

 nutrition. S. Stockman has found that an animal inoculated 

 with large numbers of dead tubercle bacilli afterwards gives the 

 tuberculin reaction. 



Practical Conclusions. From the facts above stated with 

 regard to the conditions of growth of the tubercle bacilli, their 

 powers of resistance, and the paths by which they can enter the 

 body and produce disease (as shown by experiment), the manner 

 by which tuberculosis is naturally transmitted can be readily 

 understood. Though the experiments of Sander show that 

 tubercle bacilli can multiply on vegetable media to a certain 

 extent at warm summer temperature, it is doubtful whether all 

 the conditions necessary for growth are provided to any extent 

 in nature. At any rate, the great multiplying ground of tubercle 

 bacilli is the animal body, and tubercular tissues and secretions 

 containing the bacilli are the chief, if not the only, means by 

 which the disease is spread. The tubercle bacilli leave the body 

 in large numbers in the sputum of phthisical patients, and when 

 the sputum becomes dried and pulverised they are set free in 

 the air. As examples of the extent to which this takes 

 place, it may be said that their presence in the air of rooms 

 containing phthisical patients has been repeatedly demonstrated. 

 Williams placed glass plates covered with glycerin in the 

 ventilating shaft of the Brompton Hospital, and after five days 

 found, by microscopic examination, tubercle bacilli on the surface, 

 whilst Klein found that guinea-pigs kept in the ventilating shaft 

 became tubercular. Cornet produced tuberculosis in rabbits by 

 inoculating them with dust collected from the walls of a con- 

 sumptive ward. Tubercle bacilli are also discharged in consider- 

 able quantities in the urine in tubercular disease of the urinary 

 tract, and also by the bowel when there is tubercular ulceration ; 

 but, so far as the human subject is concerned, the great means 

 of disseminating the bacilli in the outer world is dried phthisical 

 sputum, and the source of danger from this means can scarcely 

 be overestimated. Every phthisical patient ought to be looked 

 upon as a fruitful source of infection to those around, and should 

 only expectorate on pieces of rag which are afterwards to be 

 burnt, or into special receptacles which are then to be sterilised 

 either by boiling or by the addition of a 5 per cent, solution of 

 carbolic acid. 



