THE RELATIVE PREVALENCE OF HUMAN AND BOVINE TYPES OF TUBERCLE BACILLI IN BONE AND JOINT TUBERCULOSIS OCCURRING IN CHILDREN.

The all important point revealed by the investigation is the fact that a large proportion of bone and joint tuberculosis occurring in children in Edinburgh owes its origin to infection by the bovine bacillus. The bovine bacillus is introduced into the system practically by one route only, that of ingestion, and the medium with which it is ingested is cow's milk. It is not my intention to criticize in any way the existing conditions of milk supply. I have furnished proof of what is actually occurring and no one will deny that the evil is a remediable one. In those cases in which the human bacillus was present, a considerable proportion showed a definite history of pulmonary tuberculosis affecting a co-resident, and every fact went to prove that the infection had been a direct one from patient to child. A complete distinction can be drawn between human and bovine bacilli, and the distinction is best secured by subjecting the organism to a series of tests such as I have detailed. The subject is one which ought to be investigated in a series of different localities. It is possible that the locus may be a factor in the explanation of the difference between the above results and those of other observers.