"If the dog can become tuberculous from contact with man, the converse is equally true. Infection is at any rate possible when a house-dog scatters on the floor, carpet, or bed, during its fit of coughing, virulent material, which is rendered extremely dangerous by drying, especially for children, its habitual playmates. The most elementary prudence would recommend the banishment from a room of every dog which coughs frequently, even though it only seems to be suffering from some common affection of the bronchi or lung."
Tuberculosis is a common disease among the birds of the poultry-yard: poultry, pigeons, turkeys, pea-fowl, guinea-fowl, etc. They are infected almost exclusively through the digestive tract, generally by devouring infected secretions of previous tubercular fowls. Whatever the position or form of avian tuberculosis, the bacilli are present in enormous numbers, and are often much shorter and sometimes much longer than those met with in tuberculous mammalia, and grow outside the body at a higher temperature (43° C.). They are also said to be more resistant and of quicker growth. The species is probably identical with Koch's bacillus, though there are differences. In the nodule, which is larger than in human tuberculosis, there are few or no giant cells, and it does not so readily break down.
Nocard and others have demonstrated the fact that the Bacillus tuberculosis of Koch is the common denominator in all tubercular disease, whatever and wherever its manifestations, in all animals. The bacillus, they hold, may, however, experience profound modifications by means of successive passages through the bodies of divers species of animals. But if the modifications which it undergoes as a result of transmissions through birds, for example, are profound enough to make the bacillus of avian tubercle a peculiar variety of Koch's bacillus, they are not enough, it is generally believed, to make these bacilli two distinct species.
We may, therefore, take it for granted that tuberculosis is one and the same disease, with various manifestations, common to man and animals, intercommunicable, and having but one vera causa: the Bacillus tuberculosis of Koch.
The Prevention of Tuberculosis. At the present time much attention is being directed to the administrative personal control of tuberculosis. How greatly this is needed in so preventable a disease is evident from a perusal of the following quotation from the Registrar-General's reports. (See opposite page.)
These figures show a marked decline in the three worst forms of the disease. But this decline is apparently less marked in tabes than in phthisis or tubercular meningitis, i. e., less in the kind of tubercle due to the ingestion of infected milk. Fortunately the State is beginning to realise its duty in regard to preventive measures. The abolition of private slaughter-houses, the protection of meat and milk supplies, the seizure of tuberculous milch cows, and such like measures fall obviously within the jurisdiction of the State rather than the individual, and claim the earnest and urgent attention of the public health departments of states.[94]
ENGLISH DEATH-RATES FROM ALL TUBERCULAR DISEASES
THE FOLLOWING IS A TABLE OF DEATH-RATES TO A MILLION LIVING (ENGLAND), 1877–1897 (Reg.-Gen. Annual Reports):—