Annudl Report for 1911 of Royal Veterinary College. 359 



human or of the bovine type, they had been taken in with food 

 materials — that is to say, the bacilli had become effective 

 through being swallowed. Twenty-nine of these cases were 

 of so-called primary abdominal tuberculosis, and the remaining 

 nine were cases in which the glands of the neck wei*e diseased. 

 In the first of these series it was found that the lesions 

 contained the bovine type of tubercle bacillus in fourteen cases, 

 and the human type of tubercle bacillus in thirteen cases. In 

 the remaining two cases of this series the lesions contained a 

 mixture of the two types of tubercle bacilli. 



In the second series six cases contained the human type of 

 bacillus, and the remaining three the bovine type of bacillus. 



It will thus be seen that in no fewer than seventeen cases 

 out of a total of thir|^-eiglit cases of primary alimentary tuber- 

 culosis selected at random the disease was caused by bovine 

 tubercle bacilli. Thus, even leaving out of account the two 

 cases in which both types of bacilli were simultaneously 

 present, in this series of tuberculous human beings the disease 

 was proved to have been caused by bovine tubercle bacilli in 

 ■45 per cent, of the cases. As emphasising the importance of 

 these facts it must be observed that the bacilli were proved to 

 be of the bovine type by the characters which Professor Koch 

 had himself indicated as those by which that type can be 

 definitely identified. 



Not only the investigations of the British Royal Commis- 

 sion, but also inquiries conducted on parallel lines in other 

 countries, have proved that in human beings infection ])y way 

 of the alimentarj'^ canal is by no means a rare occurrence, 

 especially in young subjects. One cannot pretend to say what 

 proportion cases of this kind have to the total number of cases 

 of tuberculosis in human beings, but probably it is not less 

 than 3 or 4 per cent. ; and, taking this as the basis of calcula- 

 tion, it follows that a large number of persons in this country 

 are annually infected with tubercle bacilli which have been 

 derived from cattle. 



But, of course, the Royal Commission did not confine their 

 investigations to cases of human tuberculosis in which the 

 disease appeared to have been set up by bacilli that had been 

 swallowed. They also submitted to investigation forty-two 

 cases of so-called " consumption," or pulmonary tuberculosis. 

 In all of these cases with the exception of two the bacilli 

 present were found to be the human type, but in two cases 

 the evidence was perfectly clear that the lung disease was 

 caused by bovine tul^ercle bacilli and by these alone. 



In three cases of general tuberculosis which were investi- 

 gated and in three of tuberculosis meningitis the lesions 

 yielded human tubercle bacilli only. 



