PREVENTION OF TUBERCULOSIS 357 



of bacilli of which the chief is the B. pseudo-tuberculosis of Pfeiffer.* 

 Other workers have described very similar organisms. 



described the favourable house for such persons as one built upon a soil which is dry 

 naturally or freed by artificial means from the injurious influences of dampness and 

 of the fluctuations of the ground water. The house itself should be so constructed as 

 to be protected against dampness of site, foundations, and walls. Upon at least two 

 opposite sides of the dwelling-house there should be enough open space to secure 

 ample movement of air about it, and free exposure to sunlight. Lastly, it should be 

 possible to have free movement of air by day and night through all habitable rooms 

 of the house. It is clear many inhabited houses could not stand these tests ; but 

 effort should be made to approach as near to such a standard as possible. 



17. Tubercle-infected Houses. Many authorities have demonstrated the fact that 

 dust in houses may contain the tubercle bacillus, and that thus, presumably, persons 

 may become infected. In 1904, Klein found living tubercle bacilli in the sweepings 

 of the floors of public-houses, and some fifteen years ago Cornet published the 

 result of his investigations into the infectivity of the dust found in the dwellings 

 of consumptives in Berlin, and some work of a similar character has been done in 

 England by Coates. * 



These investigations consisted of bacteriological examinations of dust collected in 

 houses of three types : 



(a) Dirty houses in which a consumptive patient is living who takes no precau- 

 tions to dispose of his expectoration, but spits freely upon the floor and into his 

 pocket handkerchief. In 6 6 '6 per cent, of these houses virulent tubercle bacilli were 

 found showing the large amount of dangerous infective material present in an in- 

 fected house. 



(6) CJean houses in which a patient is living who is not sufficiently careful as to 

 the disposal of his sputa. In 50 per cent, of these instances the bacillus was found. 

 It is evident that ordinary household cleanliness alone is insufficient to prevent the 

 accumulation of infective material in rooms occupied by a consumptive. 



(c) Very dirty houses in which there had been no case of consumption for some 

 years. In this class of house no tubercle bacilli were present, showing that virulent 

 dust found in classes 1 and 2 must have been due to the presence of the consumptive 

 patient. 



Taking the first two classes, the average of houses infected was 61 per cent. 

 Cornet's similar work resulted in finding 71 per cent, tubercle infected. 



It was ascertained that the dust nearer the floor than the ceiling possessed the 

 greatest virulency. It was also shown that the infective dust was most virulent in 

 cases where the access of sunlight and free circulation of air was prevented, while, 

 conversely, the beneficial effect of light and air was demonstrated even in the dirtiest 

 houses. Instances were given of the dangers attaching to infected rooms, and the 

 risk to healthy occupants arid their successors. According to Koch, "it is the over- 

 crowded dwellings of the poor that we have to regard as the real breeding-places of 

 tuberculosis. " 



18. Sunlight and fresh air are the greatest enemies to infection. 



19. Disinfection is necessary after death from phthisis, and should be as complete 

 as after any other infective disease. Compulsory notification of fatal cases and 

 compulsory disinfection have been officially ordered by the Prussian Government. 

 In this country, also, absolute disinfection should always be insisted upon after 

 phthisis. Walls, floors, carpets, curtains, etc., should be strictly disinfected. 

 Spraying with 1-100 solution of chloride of lime, or other similar disinfectant, is 

 the best method (see p. 444). 



* The pathology and etiology of pseudo-tuberculosis is fully treated of by 

 Klein in the Supplement to the Twenty-Ninth Annual Report of the Local Government 

 Board, 1899-1900, pp. 355-384. See also Annales de rinstitut Pasteur, 1894, No. 4, 

 and Jour, of Path, and Bact., 1898, pp. 160-181 (Muir). 



* Trans. Brit. Gong, on Tuberculosis, 1901, vol. ii., pp. 88-101. 



