42 SCIENCE AND THE STATE, ETC. 



emus, and other birds in zoological gardens, develop' tuber- 

 culosis ; monkeys in captivity, pheasants in preserves, and 

 rabbits in /overcrowded warrens, sometimes die iii great num- 

 bers. These examples point to the conclusion that confine- 

 ment, over-crowding, defective ventilation, heredity and breed- 

 ing in and in, are powerful factors in rendering the tissues 

 prone to tubercle, and a fitting soil for the invasion of the 

 bacilli. We must also remember the danger of damp houses, 

 and the efiect of a cold and a foggy climate. In addition to 

 general insanitary conditions, I desire to draw particular atten- 

 tion to the influence of alcoholism. This was brought most 

 forcibly before the London Congress in an exhaustive paper 

 by Dr. Brouardel. The influence of previous diseases ha.*? been 

 urged by Dr. Goodhart ; and special trade occupations which 

 involve inhalation of dust of various kinds, must not be over- 

 looked. I trust that much weight will be given to these 

 matters by the Queensland Society for the Prevention of 

 Consumption. 



HEREDITY. 



I should like to say a few words on the subject of heredity. 

 Heredity is of two kinds. There is hereditary pre-disposition, 

 and hereditary transmission. Inherited susceptibility renders 

 many liable to the development of tubercular disease. Family 

 history plays a very important part in tuberculosis. Sir 

 Richard Powell stated to the Commission that in his experience, 

 48 per cent, of the cases in the hospitals suff'ering from 

 tuberculosis had a previous history of hereditary tuberculosis. 

 Dr. Klein and Mr. Victor Horsley are convinced that there 

 is direct transmission of the virus of tubercle in some 

 cases, and that it may exist for many years in a latent 

 form. In connection with the question of heredity, some 

 interesting observations have been recorded upon tuberculosis 

 in birds. According to Dr. Baumgarten, a male bird on a 

 poultry farm developed tuberculosis. All the chickens reared 

 from this parent were tubercular. There was no evidence 

 of infection with either human or bovine tubercle. An 

 identical case occurred on another farm, and these instances 

 have been quoted in support of the theory of direct transmis- 

 sion of the virus from the parent. Tuberculosis is not a com- 

 mon disease in calves, and it seems probable that these cases 

 which do occur are mostly, if not entirely, the result of 

 hereditary transmission. 



